Protestors carry signs and chant before a campaign event for U.S. Republican presidential candidate Donald Trump at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

Protestors carry signs and chant before a campaign event for U.S. Republican presidential candidate Donald Trump at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump enters a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump enters a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump holds up a piece of paper to show the audience at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump holds up a piece of paper to show the audience at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump reads the lyrics of Al Wilson's "The Snake" at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump reads the lyrics of Al Wilson's "The Snake" at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 The Secret Service detail for U.S. Republican presidential candidate Donald Trump stands watch as he signs autographs at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

The Secret Service detail for U.S. Republican presidential candidate Donald Trump stands watch as he signs autographs at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 Supporters pull U.S. Republican presidential candidate Donald Trump back to the rope line after a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

Supporters pull U.S. Republican presidential candidate Donald Trump back to the rope line after a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

 Protestors carry signs and chant before a campaign event for U.S. Republican presidential candidate Donald Trump at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump enters a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump holds up a piece of paper to show the audience at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump reads the lyrics of Al Wilson's "The Snake" at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 The Secret Service detail for U.S. Republican presidential candidate Donald Trump stands watch as he signs autographs at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 Supporters pull U.S. Republican presidential candidate Donald Trump back to the rope line after a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich
 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.
 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.
 The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. 

OR

A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.
 U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

Protestors carry signs and chant before a campaign event for U.S. Republican presidential candidate Donald Trump at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump enters a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump holds up a piece of paper to show the audience at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump reads the lyrics of Al Wilson's "The Snake" at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

The Secret Service detail for U.S. Republican presidential candidate Donald Trump stands watch as he signs autographs at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

Supporters pull U.S. Republican presidential candidate Donald Trump back to the rope line after a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

U.S. Republican presidential candidate Donald Trump speaks at a campaign event at University of Northern Iowa in Cedar Falls, Iowa January 12, 2016. REUTERS/Mark Kauzlarich

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

The Republican debate on FOX Business network as seen at the High Life Lounge in Des Moines, IA. OR A photo of U.S. Republican presidential candidate Donald Trump stands over the fence at the home of George Davey, a formerly registered independent turned Republican Trump supporter. Davey puts up signage every election at his home off Jordan Creek Parkway and Pommel Place in Des Moines, IA.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul holds an event and shoots an AR-15 at CrossRoads Shooting Sports in Johnston, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

U.S. Republican presidential candidate Rand Paul visits the Iowa for Rand Paul campaign headquarters during the "March to a Million" phone campaign in Des Moines, IA January 17, 2016.

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