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Former Massachusetts Gov. Mitt Romney greets volunteers at his 'National Call Day' fundraising event at the Las Vegas Convention Center May 16, 2011 in Las Vegas, Nev. - 

Kai Ryssdal: Depending on how you look at it, the field of potential Republican presidential candidates is either shrinking, growing or staying about the same size. Indiana governor Mitch Daniels said no thanks early Sunday morning. Today, Tim Pawlenty, the former governor of Minnesota, announced that he's in. Donald Trump said he might get back in today -- 'stranger things have happened' were his actual words.

They're fighting for political support -- and cash donations. The election next year will hinge on some big policy issues: domestic and foreign. Also, campaign finance -- that is, how much money the candidates raise.

With no clear frontrunner, that could spell trouble for Republicans as they try to find a nominee in what could be a billion-dollar campaign. From Washington, Marketplace's David Gura reports.

David Gura: No one in the GOP is blase about President Obama's billion-dollar goal.

Clayton Yeutter: Back in my era, we would not have contemplated that for a dozen presidential campaigns.

That's Clayton Yeutter. He was chairman of the Republican National Committee in 1991 and '92.

Yeutter: Fundraising is important not only in raising money, but in getting the word out.

Jim Nicholson chaired the RNC during the 2000 campaign. He says, at this point, it's all about persuasion.

Jim Nicholson: They have to be able to organize and inspire and motivate and convince people that they're the person and that they should help them by writing them a check.

Right now, the Republican candidates are fighting for donations, but with so many candidates, things could get messy. Fred Malek was George H.W. Bush's campaign manager, and he co-chaired the McCain campaign's finance committee in 2008. He says Republicans have to look beyond the big donors because they overlap.

Fred Malek: There are even some people who give to multiple candidates at this stage of the game, not knowing which one is going to be the nominee, but wanting all of them to have a shot.

A successful candidate has to be able to build a new base of smaller donors. Governor Mitt Romney, who has lots of friends on Wall Street, has raised the most money so far. But Malek says you can't rule out the rest -- the Iowa caucuses are still nine months away.

Malek: You can run from behind, and you can run a successful campaign, without having a financial advantage.

But he says you have to be skilled campaigner with a strong message. And of course, the sooner the field narrows and the GOP has its nominee, the more energy -- and resources -- it can use to challenge President Obama.

In Washington, I'm David Gura for Marketplace.

Follow David Gura at @davidgura