On the final day before the Iowa caucuses, it's all about the entourage. 

The Republican presidential candidates were hitting the trail Monday with some high-powered surrogates, as they try to convince Iowans their respective campaigns are a bandwagon they ought to climb aboard. 

The parade of endorsers following around the candidates, ideally, will serve as a reminder of their broader appeal, as each candidate tries to build the case that he or she is eminently electable on the national stage. The supporters also help the candidates do a bit of last-minute legwork, articulating the campaign message in interviews and on the stump. 

Mitt Romney had arguably his most prominent backer -- New Jersey Gov. Chris Christie -- out on the trail last week, when he memorably told Romney's supporters that if they don't turn out Tuesday, "I'll be back, Jersey style." On Monday, Romney was campaigning again with South Dakota Sen. John Thune, as well as Romney's wife and sons, in Davenport, Iowa. 

Rick Perry, whose campaign has stumbled repeatedly since his blockbuster entrance over the summer, had one of the biggest entourages in Iowa Monday. On the Perry bandwagon were Steve Forbes, Louisiana Gov. Bobby Jindal and Kansas Gov. Sam Brownback, among others, packing in a day of meet-and-greets in the Hawkeye State. 

Perry, perhaps more than any candidate save for Newt Gingrich, is trying to make the argument that he has the infrastructure and support in place to compete nationally regardless of what happens in Iowa. 

"We'll be going across the country," Perry told Fox News, claiming that fellow social conservatives Rick Santorum and Michele Bachmann just don't have the kind of operation in place that he does. 

Bachmann's support in Iowa has withered since she won the Ames Straw Poll over the summer. Santorum's, though, has surged. And his campaign just picked up a surrogate from the Bachmann team, Fox News has learned. Ron Carey, Bachmann's former chief of staff, plans to be with Santorum on Tuesday. 

Bachmann also recently lost a top Iowa backer, state Sen. Kent Sorenson, to Ron Paul's campaign. 

On the trail Monday, Paul brought out his closest campaign surrogate -- Kentucky Sen. Rand Paul, his son. 

The two launched a one-day statewide tour in Des Moines Monday, where Ron Paul touted the following his campaign has amassed. 

"I'll tell you what, the enthusiasm is growing by leaps and bounds. The crowds are getting bigger," Paul told a cheering crowd. 

Paul's numbers have been slipping slightly in recent polls, but a new Public Policy Polling survey out Monday showed him leading the field by 1 point, followed by Romney and Santorum. Paul said in interviews over the weekend that his base of support is not going anywhere and predicted a first- or second-place finish on Tuesday. 

Gingrich, too, has spent a lot of time campaigning with his family lately, though his kids are not office-holders. Among his most prominent political supporters is Art Laffer, the late President Ronald Reagan's former economic adviser. 

Gingrich cited the endorsement Sunday as a sign that "my plan was much better for economic growth and jobs." 

On Monday, Gingrich downplayed expectations for his performance in the Iowa contest, but continued to argue that he has what it takes to compete nationally and govern effectively. 

Pointing to his record as House speaker, he said: "Everyone else would be an amateur in the Obama tradition who would not know what they were doing or how to do it if they won."