Likely Republican presidential candidates Tim Pawlenty and Mitt Romney are quietly but aggressively wooing Members of Congress for endorsements and political support in campaigns that have yet to officially take flight.

The field of potential GOP candidates is crowded. But Minnesota’s Pawlenty and Massachusetts’ Romney appear to be among the most active in recruiting Members’ support. Each former governor has a small team on the ground in Washington, D.C. The team responsibilities include building the foundation for extensive backing among Congressmen and Senators, particularly those who serve in the early primary states, once their candidacies become official.

“I’ve been trying to make connections and offer opportunities to my friend, Tim,” said Rep. Erik Paulsen (R-Minn.), who along with House Education and Workforce Chairman John Kline (R-Minn.) constitutes Pawlenty’s de facto whip team. “I really want to do whatever I can to help him. Part of that is introducing him to people.”

Coordinating efforts for Romney is Drew Maloney, CEO of Ogilvy Government Relations and an old Capitol Hill hand. Team Romney expects to receive significant support from many, though not all, of the Members who endorsed his 2008 presidential bid. A key component of Romney’s strategy for maintaining old connections and cultivating new relationships has been to generously donate through his Free and Strong America Political Action Committee.

Like Romney and several other potential Republican presidential candidates, Pawlenty prodigiously contributed to GOP Members and candidates during the 2010 cycle, through his Freedom First PAC. But an important part of Pawlenty’s strategy has been to steadily build relationships with Republican Members he believes could be helpful in a crowded and competitive primary.

According to a knowledgeable source, Pawlenty’s aim has not just been to accrue endorsements, but to open lines of communication with both the important Republican Members from the early caucus and primary states as well as those viewed as political and ideological leaders generally — regardless of the role their states play in the nominating process. Along these lines, Pawlenty identified Rep. Jim Jordan last year as a rising conservative star and began trading calls with the Ohio Republican.

Jordan is now chairman of the conservative Republican Study Committee. Pawlenty has also established a relationship with freshman Rep. Sean Duffy (R-Wis.), who is set to introduce the Minnesotan at the Conservative Political Action Conference on Friday. Duffy won in a historically Democratic district last November.

“It’s not all about endorsements, at least to us,” said one Republican operative who is aiding Team Pawlenty. Instead, it’s about conversations that put a “network in place” should the campaign be successful. Among the Republican operatives assisting Pawlenty are former Rep. Vin Webber (Minn.) and consultants Phil Musser and Terry Nelson, who last cycle advised the National Republican Senatorial Committee.

Romney is taking a similarly subtle approach to cultivating Members’ support for his White House bid, particularly when compared with his effort four years ago. That strategy included a very public push to garner Capitol Hill endorsements.

However, despite being one of the early leaders among Republican candidates in terms of Member backing, Romney quickly fell out of contention, losing both the Iowa caucuses and the New Hampshire primary. This time around, Romney hasn’t slowed down contributions to Members, but he has moved with a lighter footprint in Washington.

One Republican lobbyist aiding Romney described his Member relations effort at this point as a “miniature whip effort.” The operative said Romney might not score the level of endorsements he did in 2008 but attributed that to Members being less willing to endorse than they were during the previous election.

“But there’s no question that Romney’s the most organized and active in terms of courting Members,” the lobbyist added. Romney’s strategy also includes targeting key Republicans from the early caucus and primary states, as well as Members considered to be among the GOP’s “thought” leaders. For example, someone like Sen. Jim DeMint (S.C.) could be considered an important and influential potential endorsement.

The field hoping to challenge President Barack Obama is taking shape later this cycle than the last, causing many Members to refrain from revealing their favorite ahead of an official candidate announcement. Still, others are pledging to get involved on a very limited basis, with others vowing to remain neutral.

Sen. Orrin Hatch (R-Utah) is among the exceptions, making clear last week that he is committed to Romney and willing to help in any way he can. However, Sen. Richard Burr (R-N.C.) said he would only endorse Sen. John Thune, should the South Dakota Republican get into the race. Thune has said he will announce a decision by month’s end.

Senate Republican Conference Chairman Lamar Alexander (Tenn.) told Roll Call he intends to remain neutral.

“I think we have a number of exceptional candidates,” said Alexander, who ran for president in 1996. “I’m going to step back and give them all a chance to make that decision and try to create an environment in which one of them can win.”

With Washington having fallen out of favor, particularly with the conservative voters who tend to populate Republican primaries, receiving the public endorsement of a Member of Congress might carry less heft than it did in previous cycles.

Still, a Congressman’s backing can give a candidate access to expanded political and fundraising contacts, as well as local, grass-roots infrastructure. Additionally, an endorsement can enhance a candidate’s image in the primary, if, for instance, the backing comes from a Member supported by tea party activists or conservative groups such as the Club for Growth.

Gregg Hartley, vice chairman and chief operating officer of Cassidy & Associates who was a part of the Congressional relations team for the 2000 campaign of then-Texas Gov. George W. Bush, said the key to profiting from an endorsement is using it properly. Rather than unveiling endorsements from Washington, he advised candidates to publicize them locally and with a parochial spin, so voters associate the candidate with the popularity of that Member.

“Once a Member of Congress commits, he brings his entire political apparatus to your campaign. That’s what the Bush folks understood,” Hartley said by telephone from Dubai. “That’s real value.”