When Sen. John Thune and Rep. Mike Pence (Ind.) opted against 2012 presidential bids, that left just two potential candidates serving in Congress, Reps. Ron Paul and Michele Bachmann. While both are long shots to secure the GOP nomination, Paul and Bachmann have tea party cred that could come in handy should they give it a try.

But the bench is deep when it comes to the No. 2 slot on the ticket to challenge President Barack Obama.

These Members of Congress are likely to be on any nominee’s longish short list for vice-presidential contenders come 2012. Here are a few pros and cons about each.

Sen. Kelly Ayotte

New Hampshire

Pros: Elected in the often-swing state last fall, Ayotte could boost a conservative, Southern male nominee looking for a fresh face to help with independents.

Cons: Gov. John Lynch is a Democrat and could appoint an interim replacement from his party should Ayotte be part of a winning ticket.

Rep. Michele Bachmann

Minnesota

Pros: She has proved she can mobilize Republican voters, and she also can raise money. Her 2010 re-election bid was the most expensive in the country, thanks in part to her fundraising prowess. She’s popular among Republicans back home and could make the Democratic-leaning state competitive.

Cons: Among the possible candidates, Bachmann’s list of negatives is the longest. Many Republicans view her as too extreme and unwilling to work with party leaders. As she considers her own presidential bid, Bachmann has made multiple gaffes. She also inflames liberals and would help Democrats galvanize anti-Bachmann voters.

Sen. Scott Brown

Massachusetts

Pros: He has a national profile and symbolizes the beginning of Republicans’ comeback after President Barack Obama’s historic victory. He has fundraising chops and a moderate voting record.

Cons: Even with Brown on the ticket, the GOP is unlikely to win Massachusetts’ electoral votes. Plus he’s popular in the Bay State and polls well for 2012 re-election. Brown could stay on the ballot for Senate and vice president, but putting him on the national ticket puts the GOP seat at risk.

Rep. Eric Cantor

Virginia

Pros: Long an up-and-comer in the party, the House Majority Leader was briefly considered a possible running mate for Arizona Sen. John McCain in 2008. He’s been vetted, and his support at home could help Republicans recapture Virginia’s electoral votes in 2012. Cantor, who is Jewish, also has a broad base of national support.

Cons: He could be too much of an insider at a time when the establishment is less than popular, and he has a long voting record Democrats could scrutinize. He also has his eye on being Speaker.

Sen. Jim DeMint

South Carolina

Pros: The rock-ribbed fiscal and social conservative could boost a moderate nominee. DeMint has a national profile thanks to his Senate Conservatives Fund, and the tea party considers him a hero.

Cons: He’s not very popular with his own party in Washington, and several prominent Republicans still hold a grudge for his interference in the 2010 Senate primaries that cost the party a handful of seats.

Sen. Ron Johnson

Wisconsin

Pros: He’s from a battleground state that Republicans promise to target in 2012, and he unseated longtime Sen. Russ Feingold (D) last fall. A businessman who ran as a Washington outsider, he could help an establishment Republican on the ticket.

Cons: He has nearly zero national name recognition and no political experience beyond his few months in the Senate.

Rep. Kevin McCarthy

California

Pros: A rising leader in the House GOP, this blue-state Republican could be attractive for a candidate trying to put the Golden State in play.

Cons: California is highly unlikely to flip to the Republicans in a presidential year, and running for vice president would require McCarthy to skip re-election and forsake his spot as Whip.

Rep. Kristi Noem

South Dakota

Pros: She represents the new face of the Republicans as part of the freshman wave of 2010. Already, Republicans chose her to deliver their weekly radio address and have elevated her as a Member with a bright future.

Cons: She just got to Washington and is not well-known. She also would not bring geographic diversity to Republicans seeking a balanced ticket.

Rep. Ron Paul

Texas

Pros: Paul has a fanatical, if not enormous, base of national support that proved surprisingly resilient in a 2008 race that was stacked against him. He perfected fundraising on the Internet.

Cons: Paul, 75, is not representative of the party’s future. His ideas would be painted as extreme in a national race.

Sen. Rob Portman

Ohio

Pros: He has experience as a budget guy in the Bush administration, plus he comes from a battleground state each side considers a must-win. He’s been helping all 2012 candidates get acquainted with Ohio behind the scenes.

Cons: His strong résumé in budget and trade roles could make him too much of an insider in a national election. His ties to President George W. Bush could be a setback.

Sen. Marco Rubio

Florida

Pros: It’s no secret Rubio is the favorite VP choice among Republicans in Washington. He’s handsome, young, from an important battleground state and can attract Latino voters with his Cuban heritage. He has tea party support but has shrewdly avoided becoming a spokesman for their movement. He served as Speaker of the Florida House.

Cons: He just got to Washington. On the other hand, tell that to Barack Obama, who announced his presidential bid just two years into his first Senate term.

Rep. Paul Ryan

Wisconsin

Pros: As one of the GOP’s “Young Guns,” Ryan, 41, is gaining national attention as a frequent television guest and go-to policy guy in Washington. He’s liked by tea party activists. As the Budget chairman, Ryan is seen as the party’s idea man, unafraid to tackle tough issues such as entitlement spending.

Cons: Like the others in House leadership, Ryan would have to give up a lot for a spot on the ticket. He may also have future presidential ambitions of his own.

Sen. John Thune

South Dakota

Pros: He has a record as a giant-slayer for unseating then-Minority Leader Tom Daschle in 2004 and for winning tough races previously. He had no opposition for re-election in 2010. He looks the part and has a conservative voting record. The other candidates may appreciate that he opted against his own bid.

Cons: Like Noem, Thune wouldn’t bring geographic diversity to the ticket.

Sen. Pat Toomey

Pennsylvania

Pros: As the former leader of the conservative Club for Growth, Toomey has some national credentials that could translate well to a presidential ticket. He just won in a battleground state that has favored Democrats in recent national elections.

Cons: Democrats would paint him as an extremist for his conservative views. Since Toomey also is a former House Member, he’s not exactly a face for change.