The four main candidates for the Republican nomination for president say they're committed to staying in the race right up to the party's convention this August in Tampa, Fla.

There's just one problem: If they do, it might turn out that no one gets the number of delegates needed to win the nomination outright.

Stumping in Birmingham, Ala., Mitt Romney continued his Southern charm offensive, celebrating an endorsement from the country band Alabama. "Wouldn't you love to hear them sing 'Sweet Home Alabama'? Wouldn't that be wonderful?" he asked a crowd at one campaign stop.

In the race to rack up delegates, Romney has a commanding lead: 396, to Rick Santorum's 146. Newt Gingrich trails with 97, and Ron Paul has 38.

But with four candidates splitting the vote, Romney may not get the 1,144 delegates he needs to clinch the nomination before the convention.

It's exactly the scenario his opponents are hoping for.

"Everybody knows these delegates who are up for grabs, very few are hard-committed," Rick Santorum contended.

Santorum said Friday he's preparing for the possibility of a "contested convention" in which he would try to persuade some of Romney's delegates to change their votes.

Gingrich said he intends to do the same. "We want to make case," Gingrich says, "to all the delegates who are not legally bound that, in fact, the other two candidates cannot beat (President) Obama. And if they come to that conclusion, I think the convention may end up being one of the most surprising in modern times."

Contested conventions don't have a history of ending well.

President Gerald Ford survived a contested convention in 1976, but was defeated in the general election by Jimmy Carter. And back in 1952, Adlai Stevenson eeked out a victory at the Democratic convention, only to fall to Dwight Eisenhower.