Mr. Romney has been by far the most assertive, according to interviews with a half-dozen top Republican fund-raisers, already pushing for commitments from major donors should he formally decide to run.  Over the summer, Mr. Romney, the former Massachusetts governor, invited top bundlers of campaign checks from key states to his vacation home in New Hampshire on several occasions to help firm up their commitments. Mr. Romney has already lined up an array of prominent supporters, including a billionaire, David Koch, who has donated heavily to conservative causes over the years, and Robert Wood Johnson IV, the billionaire owner of the New York Jets and one of the party’s most coveted fund-raisers.  Mr. Pawlenty has also been putting together a financial apparatus. On Monday and Tuesday evening, for instance, he met with top fund-raisers who flew to Minneapolis to listen to a briefing on his record as governor. Those were the latest in a series of such meetings that began in September, according to William Strong, a vice chairman at Morgan Stanley who has spearheaded fund-raising for Mr. Pawlenty’s political action committee, Freedom First.  Over the last year, Mr. Pawlenty has been methodically courting fund-raisers in get-acquainted, “friend-raiser” sessions and is now moving to deepen those relationships with a potential eye on 2012, Mr. Strong said.  Noticeably absent from the wooing for the most part has been the former Gov. Sarah Palin of Alaska, Republican fund-raisers said. She has raised large sums for her federal political action committee, Sarah PAC, this year — exceeded only by Mr. Romney — but largely through small-dollar contributions.  There have been some notable occasions where Ms. Palin has also engaged in the kind of glad-handing with major donors that typically precedes a presidential run. In early October, for example, she had dinner with a contingent of prominent Republican donors, political figures and others in West Palm Beach, Fla., for an event organized by Christopher Ruddy, head of the conservative magazine and Web site Newsmax.  “I saw it as a combination of conservative opinion leaders and some of the leading fund-raisers in Florida and some others across the country and having Governor Palin give sort of a dress rehearsal for what it would be like if she got in the race,” said Brian Ballard, a lobbyist who was the Florida finance chairman for the presidential campaign of Senator John McCain of Arizona and was among the attendees.  Even with all of the jockeying, Republican fund-raisers and operatives said that commitments for 2012 seem to be unfolding at a slower pace than the last presidential cycle, because so much uncertainty remained over who would actually run.  “People are shopping,” said Kirk Blalock, a partner at the Washington lobbying firm, Fierce, Isakowitz & Blalock, who was a top fund-raiser for the McCain campaign. “People aren’t buying yet.”  Many donors are awaiting decisions by potential 2012 candidates like Gov. Haley Barbour of Mississippi, who has been collecting giant checks in his capacity as chairman of the Republican Governors Association, which raised record amounts this year. The relationships he forged with deep-pocketed donors could double as useful building blocks for a presidential run.  There is also Gov. Mitch Daniels of Indiana. He has said he will wait until the end of his state’s legislative session in April to make a decision, but he has held fund-raisers in recent months for his state-based leadership PAC, Aiming Higher, in Chicago, Washington and New York. He did four fund-raising events in New York alone.  Senator John Thune of South Dakota, who is also contemplating entering the 2012 fray, has been sounding out top fund-raisers as well.  Newt Gingrich, the former House speaker, is one of the biggest variables. Mr. Gingrich has not been openly buttonholing major donors for a presidential bid, fund-raisers said. Nevertheless, all the work he has been doing for his policy center, American Solutions, generating large contributions (the group is permitted to take in donations of unlimited size) and building donor lists, could form a strong financial foundation for a run.  Top fund-raisers said they had observed relatively little effort so far on the part of former Gov. Mike Huckabee of Arkansas, whose leadership PAC fund-raising has trailed that of Mr. Romney, Ms. Palin and Mr. Pawlenty, to cozy up to major donors. His supporters, however, point out that his strength has always been more at the grass-roots level.  Even with all of the uncertainty, some large donors have already made sizable investments with those who could wind up as presidential candidates.  Mr. Barbour has banked several $25,000 contributions in recent months from Mississippi corporations, like Anderson Companies, a construction firm, and Ergon, which is involved in petroleum products, through Haley’s Leadership PAC, a committee he set up in Georgia, where there are few campaign finance restrictions.  Richard Marriott, the hotel executive, and his wife, Donna, have together given Mr. Romney $225,000 this year mainly through the state-based affiliates of his federal PAC, Free and Strong America, in Alabama, Iowa, Michigan, New Hampshire and South Carolina.  Other major Romney contributors include Edward Conard, a former executive with Mr. Romney at Bain Capital, who donated $100,000, and Hushang Ansary, a Texas oil-and-gas investor and former Iran finance minister, who contributed $95,000.  The network of state PACs Mr. Romney has set up seems intended to give him leverage in some important early-voting states but also to take advantage of permissive campaign finance rules. Alabama, Iowa, and Michigan, for example, do not cap contributions to these kinds of PACs.  A version of this article appears in print on November 13, 2010, on Page A1 of the New York edition with the headline: Looking to 2012, Republicans Vie For Big Donors. Order Reprints| Today's Paper|Subscribe
Some potential candidates are pursuing outsize contributions using state political action committees, which, unlike federal PACs, have no spending limits.