For the first time in a generation, Republicans are preparing for the possibility that their presidential nomination could be decided at their national convention rather than on the campaign trail, a prospect that would upend one of the rituals of modern politics.
The race remains Mitt Romney’s to lose, and if he continues to accumulate delegates at a steady clip starting with contests in Puerto Rico on Sunday and Illinois on Tuesday, he can still amass the 1,144 necessary to secure the nomination before the last primary, in Utah on June 26.
But as he struggles to win the hearts of conservative voters and hold off a challenge from Rick Santorum, party leaders, activists and the campaigns are for the first time taking seriously the possibility that neither he nor anyone else will get to that total.
In that case, the nomination would be decided by the more than 2,200 delegates — from obscure local officials and activists to national figures — who will attend the party’s convention in Tampa, Fla., in late August.
They would embark on an unscripted, contentious and televised drama that has not played out in 36 years, a period in which both major party conventions have become slickly produced and highly choreographed pep rallies kicking off the general election campaign.
With that in mind, campaign and party lawyers are dusting off their party rule books, running through decades-old procedural arcana and studying the most recent convention-floor fight, between Ronald Reagan and President Gerald R. Ford in 1976. Republican officials also are bracing for the possibility of a prenomination clash between the party’s establishment and members of the Tea Party movement, many of whom may be attending their first national convention.
“It’s more likely than anything since ’76, there’s no question,” said Robert M. Duncan, a former Republican national chairman who was a delegate at the convention that year and presides over the Committee on Contests, the party council that would hear disputes about delegates.
Mr. Duncan and leaders across a wide spectrum of the party say a contested convention is still unlikely. They said the race was still being driven by momentum, which Mr. Duncan predicted “is going to certainly push Romney — or somebody else — to the forefront.”
Yet Mr. Santorum has hired a delegate specialist to comb through the patchwork of state-by-state rules and to find unpledged delegates who could swing to him in a floor fight, an effort Mr. Romney’s campaign says it is prepared to counter. Newt Gingrich’s team is expected to hold on to its delegates even if it is clear that he has fallen short — if only to keep Mr. Romney from reaching a majority.
And the Republican National Committee has alerted the Committee on Contests to be ready for action, preparing for the possibility of courtroomlike hearings run by lawyers that could decide whether the nomination is settled before party members take their seats in the Tampa Bay Times Forum sports arena.
The question of whether the race spills over into the convention has opened a new battleground among campaigns in the complicated system of allocating delegates in state and county party gatherings that follow the primaries and caucuses.
The process was playing out Saturday in Missouri, where Mr. Santorum urged voters to reprise his victory from a primary last month that did not allocate delegates. A caucus in St. Charles County was shut down early and the police were called when people in the crowd began chanting, “We make the rules!”
The burden of avoiding a convention fight largely rests on Mr. Romney and whether he can overcome his rivals in the pending contests.
Mr. Romney’s campaign is working intensively to stave off the possibility, especially here in Illinois in preparation for Tuesday’s primary, which it hopes to win decisively as the start of a sustained move to shut down his rivals. He beefed up his weekend campaign schedule, and he and his allies stepped up advertising to slow Mr. Santorum.
Mr. Romney has 495 of the 1,144 delegates needed for the nomination, according to a tally by The Associated Press that includes estimates of “unbound” delegates, mostly party leaders and officials who can choose which candidate to support. By the A.P. tally, Mr. Santorum has 252 delegates, Mr. Gingrich 131 and Ron Paul 48.
Aides to Mr. Romney dismissed the notion that Mr. Santorum or Mr. Gingrich had the organizational muscle to force the party into a convention fight, but said Mr. Romney would emerge victorious even if it came to that.
“They may be planning on a contested convention, but it’s irrelevant because we’re going to get to 1,144,” said the Romney campaign’s chief counsel, Katie Biber Chen.
Forcing a Fight to the Convention
The Romney campaign is carefully monitoring Mr. Santorum’s and Mr. Gingrich’s delegate tallies and plans to label them spoilers if reaching 1,144 becomes implausible for them. At that point, Mr. Santorum and Mr. Gingrich would be running to stop Mr. Romney from doing so — a strategy that Mr. Gingrich is already discussing openly — and thereby forcing a fight to the convention.
“Roughly translated, that means, ‘We’re planning on ensuring the party can’t choose a nominee until September, with 60 days to take on an incumbent president who will have $1 billion,’ ” Ms. Chen said, referring to an often disputed estimate of Mr. Obama’s fund-raising goal.
Mr. Romney retains the same advantages that have made him the front-runner: he has the most money, the biggest and most sophisticated organization, and apparent appeal in big states in the Northeast and the West with large numbers of delegates at stake.
But those presumed advantages have failed to overcome his challenges among the more conservative Republican voters.
“In terms of the delegate count, Romney is well positioned, but I don’t think his opponents are going to go quietly,” said Senator John Thune, Republican of South Dakota and a Romney supporter. “I think there’s a hope among the other candidates that they can split this thing up enough so they can go into the convention and have it decided there.”
The jockeying in the delegate race is causing the campaigns to work through a labyrinthine set of state rules under which delegate allocation does not always track with the popular vote in primaries and caucuses.
In many cases, states award a mix of bound delegates who head to the convention under the requirement that they vote for the winner or, in some cases, the second-place finisher, in their Congressional districts, and unbound, free to vote for whom they please.
The delegates will be selected at scores of county and state party conventions that carry on through July and are now being lobbied by the presidential campaigns, which know every delegate could count.
Randy Evans, Mr. Gingrich’s lawyer and senior adviser, said that to reach 1,144, Mr. Romney would have to rely on some of the more than 100 unbound delegates from around the country who have so far given him oral commitments, and “we know in politics how valuable those are.”
Mr. Romney’s campaign said it might have to rely on such commitments, but was not concerned.
Mr. Santorum and Mr. Gingrich believe that they will have an edge over Mr. Romney among the party delegates because, as Mr. Santorum’s new delegate strategist, John P. Yob, said, “the people who show up for county, district and state conventions are much more conservative than your average primary voters.”
Mr. Yob had helped oversee the delegate process for Senator John McCain’s Republican presidential campaign four years ago. Now Mr. McCain is among the party stalwarts who hope Mr. Yob is unsuccessful.
“Every day that goes by that they campaign against each other, particularly with the tenor of this campaign, the unfavorables of Mitt Romney go up and it’s a day lost where he is not able to campaign against President Obama,” Mr. McCain said in a brief interview.
Others said the party must find a careful balance.
“A candidate certainly has his or her right to raise a concern to fight something as long as they can,” said Doyle Webb, the Arkansas Republican chairman. “I really want the Republican voters to have their say and be connected to who our nominee is, and there is no nominee who is preordained.”
Jonathan Weisman contributed reporting from Washington, and Steven Yaccino from St. Peters, Mo.