WASHINGTON - Rick Santorum is falling so far behind Mitt Romney in the race for Republican delegates that his best chance might be in states that voted weeks ago.

The chief rival to the front-running Romney, Santorum is trying to improve his lot in places like Iowa and Washington, where local caucuses were just the first step in determining delegates to the Republican National Convention. In those states and a few others, supporters are now preparing for county, congressional district and state conventions, where the campaigns hope to keep their delegates - and possibly poach some from other candidates.

Santorum's delegate count could use a boost. He trails Romney by 300 and would need to win 74 percent of the delegates in the remaining primaries to clinch the nomination before the national convention in August. So far, Santorum is winning just 27 percent, according to the tally by The Associated Press.

But the former Pennsylvania senator's campaign predicts that he will significantly increase his delegate haul in caucus states, primarily at the expense of Romney.

"The Romney campaign likes to talk about how they have this superior organization in these caucus states and therefore they are going to perform well," said John Yob, Santorum's national delegate director. "If you believe the Romney campaign's spin that they have this superior organization, but yet they're losing these contests, it must mean they have a deficient candidate who is unable to appeal to the base of the party."

That assessment is simply laughable, Romney's campaign says. And his backers question whether Santorum has a sufficient organization to compete in upcoming primaries while also trying to rally supporters in states that held caucuses weeks or months ago.

This weekend, for example, Louisiana holds its GOP primary on Saturday, the same day county conventions kick off in Washington state.

Rich Beeson, Romney's political director, notes that Santorum didn't get on the ballot in Virginia or the District of Columbia and failed to file full slates of delegates in Ohio and Illinois.

"You're all of a sudden going to be able to organize at a state convention, a county assembly, and start stealing delegates from us?" Beeson said. "We have a plan in place. We will maintain and increase our delegates at the caucus level."

Romney leads the race for delegates with 563, including endorsements from Republican National Committee members who automatically attend the convention and can support any candidate they choose. Santorum has 263 delegates, former House Speaker Newt Gingrich has 135 and Texas Rep. Ron Paul has 50.

It takes 1,144 delegates to win the Republican nomination to take on President Barack Obama in the fall.

So far, Romney has won 54 percent of the delegates at stake in primaries and caucuses. That puts the former governor of Massachusetts on pace to clinch the nomination in June, but it doesn't leave much room for error.

The last primary is June 26, in Utah, giving the other candidates hope they can stop Romney short and force a fight for delegates at the national convention in Tampa, Fla.

Six states have held local caucuses that were only the start of a multi-step process to win actual delegates. Together, those states have a total of 223 delegates, which will be up for grabs at county, congressional district and state conventions sprinkled throughout the spring.

In five of the states - Iowa, Colorado, Minnesota, Maine and Washington - the AP used local caucus results to project the number of national delegates each candidate would win if he maintained the same level of support throughout the process. The sixth state, Missouri, didn't release statewide results from local caucuses, so it was impossible to make a projection.

Santorum has more delegates in the five states than any other candidate, according to The AP tally: 73, compared to 62 for Romney, 15 for Paul and none for Gingrich.

Most of the campaigns argue they will outperform AP's projections, and the battle in some states is fierce.

In Missouri, a local Republican caucus near St. Louis was shut down without a vote after it got so rowdy that extra police were summoned to help. In Wyoming, Romney supporters successfully challenged a single Santorum delegate in Park County, getting local party officials to switch the delegate to Romney more than a week after the convention.

In Minnesota, Paul's supporters showed up at the GOP convention in Carver County lugging computers and printers so they could track their delegates and tell supporters whom to vote for.

"First time I'd seen it," said Steve Nielsen, the Carver County GOP chairman.

Despite not winning a state, Paul's supporters have been active in all the caucus states.

John Tate, Paul's campaign manager, said Paul's supporters have sometimes played kingmaker, cutting deals in counties where the original caucus vote was evenly split, resulting in a divided county convention.

In some places, they have been approached by Romney supporters looking to block Santorum's delegates. In others, they have been approached by Santorum supporters looking to block Romney.

Said Tate: "Unless you have an outright majority, cutting deals happens."

He said Santorum's campaign has shown signs of life in the caucus states, but he questioned whether it would be enough to win many delegates from Romney.

"I think his campaign is starting to figure it out," Tate said of Santorum. "But in a lot of these states, I don't see the organization that we have or that Romney has."

Associated Press writers Brian Bakst in St. Paul, Minn., and David A. Lieb in Town and Country, Mo., contributed to this report.