WASHINGTON (AP) -- Don't look for a quick winner in the race for the Republican presidential nomination. After watching Democrats successfully ride their historic primary battle between Hillary Rodham Clinton and Barack Obama all the way to the White House in 2008, the Republicans quietly adopted a new rule designed to extend their nominating process this time around.
The rule limits the ability of candidates to win large numbers of delegates in early primaries and caucuses -- those held before April -- because delegates must be awarded in proportion to the votes a candidate receives.
Many Republican state parties like to hold winner-take-all primaries because they create buzz and put a premium on candidates finishing first. Those states, however, will have to wait until April, at the earliest, to hold their nominating contests.
"The top two or three candidates have a real chance now to go deep into March and maybe early April," said Bob Bennett, a member of the Republican National Committee from Ohio. "I could see it going deep into April with a two-man contest."
Bennett served on the RNC panel that wrote the new rule in 2010. Iowa, New Hampshire, South Carolina and Nevada -- the first states expected to hold nominating contests -- were exempt.
Texas Gov. Rick Perry has emerged as the Republican front-runner, with former Massachusetts Gov. Mitt Romney his chief rival. Farther back in the polls are Rep. Michelle Bachmann of Minnesota and Rep. Ron Paul of Texas.
Despite the change, the expectation is low that GOP race will go all the way to June, like the battle between Clinton and Obama.
The Democratic race in 2008 was exceptional, pitting two well-funded, resilient candidates who were able to survive multiple losses and emerge with enough campaign money to continue. In one stretch, Clinton lost 11 contests in a row. Her campaign was wounded, and she eventually lost the nomination to Obama, but she was able to stay in the race for several more months.
No one in the GOP field could withstand 11 straight losses and still raise enough money to remain a viable candidate, said Rich Galen, a veteran Republican campaign strategist. But they could lose a majority of those races, and if they still pick up a substantial number of delegates, they might be able to persuade donors to stick with them, he said.
"If there were 100 delegates available and you got zero, then it looks like hell," Galen said. "But if there are 100 delegates and you got 40, even though you didn't come in first, you did pretty well. That translates into money and that allows you to keep going."
Another important difference between Democrats and Republicans: Democratic Party rules require all states to award delegates proportionally. In 2008, that made it harder for Obama to put Clinton away earlier. It also hurt Clinton's ability to catch up, once she fell behind.
Republican state parties can schedule winner-take-all primaries, starting in April, which should help decide the GOP contest before June.
"We felt that it would be helpful to the process to go a little longer, but not all the way to June," said John Ryder, a member of the Republican National Committee from Tennessee. He chaired the panel that wrote the new rule.
"At some point, the advantages that are gained by extending the process begin to yield diminishing returns because it begins to drain your financial base and perhaps leave the kinds of primary scars that are very difficult to heal for the general election," Ryder said.
The new delegate rule was adopted after an intense debate among GOP activists. Some worried it would extend the contest too much, increasing the possibility that the Republican candidate would emerge bloodied and broke. Others believed that a longer contest could energize the party for the general election.
The rule does not define proportional, so there will be some variation among the states on how they divvy up delegates.
For example, New Hampshire Republicans plan to allocate all 20 of their delegates proportionally, based on the statewide vote. Oklahoma Republicans plan to award some of their 40 delegates based on statewide results and the rest based on vote totals in individual congressional districts.
It's unclear which Republican candidate might benefit from the new rule because the dynamics of the race could change dramatically, depending on the outcome of early primaries and caucuses. The election calendar is also in flux.
State parties have until Saturday to submit their primary and caucus plans. Once the RNC reviews the plans, the party will set the number of delegates needed to win the nomination.
Under rules agreed to by both political parties, only Iowa, New Hampshire, Nevada and South Carolina are permitted to hold nominating contests before March 6. If other states go before that date, they could lose half their delegates to the Republican national convention in Tampa, Fla.
Nevertheless, several states are considering contests in February or even January, adding another level of uncertainty to the early days of the campaign. Those states include Florida, Michigan, Georgia and Arizona.
Many other states are holding their contests later, in April, May or June. That means Super Tuesday -- March 6 -- might not be as super as it was four years ago.
In 2008, more than 20 states held primaries and caucuses on Feb. 5, and Sen. John McCain of Arizona emerged with a commanding lead on his way to the Republican nomination. The 2012 version of Super Tuesday is shaping up to have about 10 Republican contests.
That's OK with Ryder, who said McCain was at a big disadvantage in 2008 because he locked up the GOP nomination so early.
"After that, John McCain sort of disappeared from the national consciousness," Ryder said. "Meanwhile, Barack Obama and Hillary Clinton are out there every week, getting stories and getting their ideas out, presenting them to the American people. That was very much on our minds when we drafted the rule."