It's his first trip since 2010 and a sign he's mulling a bid for the White House.
The ex-president is trying to help his party in his home state.
The 2016 hopeful has stumped for top GOP Senate candidates and governors nationwide.
The three men presented different reasons why Iowa conservatives should vote.
“There’s no telling what could happen in just a matter of a couple of years,” Carson said.
Cruz won 25 percent of votes at the annual Washington conference.
New York Gov. Andrew Cuomo will receive briefings from Pentagon officials and meet troops.
The former Arkansas governor pointed to Clinton's 2008 attack ad against now-President Obama.
Gov. Bobby Jindal charmed social conservatives with a funny and fiery speech.