Six months into the 110th Congress and approximately six months before the first primary vote is cast, Sen. Hillary Rodham Clinton (D-N.Y.) is the favorite presidential candidate among members of Congress.

Of the 196 lawmakers who have already decided who they think should be the next president, Clinton has garnered 51 endorsements, the most of any candidate.

Additionally, 22 of New York’s 23 Democratic congressmen have endorsed Clinton. Rep. Yvette Clarke, who has not yet declared her allegiance to any candidate, is the only New York Democrat who has not endorsed her.

Clinton, the current Democratic front-runner for the nomination, has also gained the support of influential members. She boasts the endorsements of House Ways and Means Committee Chairman Charles Rangel (D-N.Y.), House Foreign Affairs Committee Chairman Tom Lantos (D-Calif.) and House Rules Committee Chairwoman Louise Slaughter (D-N.Y.).

On the Republican side, Sen. John McCain (Ariz.) and former Massachusetts Gov. Mitt Romney lead with 27 endorsements each. Nine senators have backed McCain, the most of any presidential candidate. Most notably, McCain has picked up the endorsements of Senate Minority Whip Trent Lott (R-Miss.) and Senate Armed Services Committee ranking member John Warner (R-Va.). Warner’s endorsement surprised many observers because Warner and McCain have been on opposite sides of the debate surrounding the current strategy of the war in Iraq — Warner has advocated a diversion from the president’s strategy while McCain has staunchly supported it.

Romney, whose fundraising prowess has helped him gain momentum in New Hampshire and Iowa, is backed by five Republican senators — Wayne Allard (Colo.), Bob Bennett (Utah), Larry Craig (Idaho), Jim DeMint (S.C.) and Orrin Hatch (Utah) — and former House Speaker Dennis Hastert (R-Ill.).

Clinton’s top competition for the Democratic nomination, Sen. Barack Obama (Ill.), is backed by 22 lawmakers. Like Clinton, Obama has received much of his support from his home state. His only supporter in the Senate is his Illinois colleague Dick Durbin (D). Eight of 10 Democratic Illinois congressmen have also endorsed Obama. Reps. Daniel Lipinski and Rahm Emanuel are the only two Democratic Illinois lawmakers who have not endorsed Obama.

Emanuel, the chairman of the House Democratic Caucus, has been particularly coy about who he supports in the presidential race. The lawmaker has close ties to the Clinton camp, having worked on former President Bill Clinton’s campaigns and as a senior White House adviser to Clinton from 1993 to 1998. Yet his name is noticeably absent from Clinton’s list of endorsers.

Former New York City Mayor Rudy Giuliani has picked up 17 endorsements from lawmakers. Only one senator, David Vitter (La.), is backing Giuliani, and three of New York’s six Republican congressmen support Giuliani’s campaign.

Even though he has yet to enter the race officially, former Tennessee Sen. Fred Thompson (R) has garnered support from 14 lawmakers. Both Tennessee senators, Lamar Alexander (R) and Bob Corker (R), are backing Thompson. Thompson also stole two endorsements from Romney when Reps. Marsha Blackburn (R-Tenn.) and John Duncan Jr. (R-Tenn.) swung their support from the former governor to the former senator. House Republican Conference Chairman Adam Putnam (Fla.) has also backed Thompson.

Former Sen. John Edwards (D-N.C.) also has collected 14 congressional endorsements. The 2004 vice presidential nominee has yet to receive the support of any senators but is backed by every North Carolina Democratic congressman.