Gov. Chris Christie, R-N.J., visits "Face The Nation" on Feb. 26, 2012, in Washington, D.C. Christie and his take-no-prisoners style has made him an extremely popular figure in traditionally Democratic New Jersey and his blunt talk could excite voters nationwide.
Chris Christie
On the flip side, his shoot-from-the-hip style could just as easily turn off voters or draw more scrutiny to the ticket if he shoots too far. Also, he's not well-loved by the Tea Party wing of the GOP. In this photo, Romney looks on as Christie speaks during a rally at Exeter High School on Jan. 8, 2012, in Exeter, N.H.
Rob Portman
Sen. Rob Portman, R-Ohio, is seen at the 2012 Fiscal Summit on May 15, 2012, in Washington, DC. Portman is extremely popular in the Buckeye State, a key battleground this fall.
Rob Portman
But Portman held two different positions in the George W. Bush administration, something that opponents would likely use against him. In this photo, Portman introduces Romney at Meridian Bioscience on Feb. 20, 2012, in Cincinnati, Ohio.
Tim Pawlenty
In this photo, Former Gov. Tim Pawlenty, R-Minn., is seen taking a tour of the Chantland-MHS manufacturing plant on Aug. 9, 2011, in Humboldt, Iowa. Pawlenty could boost Romney with his blue-collar appeal and conservative views.
Tim Pawlenty
However, Pawlenty was a strong critic of Romney during the primaries last year, at one point dubbing the similarities between the Romney and Obama health care plans, "Obamneycare." In this photo, Pawlenty is seen speaking during a rally for Romney on Feb. 1, 2012, in Eagan, Minn.
Paul Ryan
Rep. Paul Ryan, R-Wisc., is introduced before speaking about "America's Enduring Promise," and the federal budget, in a speech at Georgetown University on April 26, 2012, in Washington, DC. Ryan brings energy and experience to the ticket; at 42, he's already in his 7th term in the U.S. House.
Paul Ryan
Ryan's budget proposal has been sharply criticized by opponents with some saying its potential effect on Social Security and Medicare could turn off older voters. Romney and Ryan hold bags of food at a Culver's restaurant on April 1, 2012, in Johnson Creek, Wis.
Bobby Jindal
Gov. Bobby Jindal, R-La., speaks to guests at the Conservative Political Action Conference (CPAC) at the Donald E. Stephens Convention Center on June 8, 2012, in Rosemont, Ill. Jindal would bring varied experience to the ticket: executive, legislative and bureaucratic.
Bobby Jindal
Jindal, however, was heavily criticized in 2009 after delivering a lackluster response to President Obama's speech to a joint session of Congress. After Jindal's speech, political observers questioned his readiness for the national stage. Jindal speaks during the NRA's Celebration of American Values Leadership Forum at the NRA Annual Meetings and Exhibits on April 13, 2012, in St. Louis, Missouri.
Marco Rubio
Sen. Marco Rubio, R-Fla., is seen at a seminar on "Is the American World Order Sustainable and Necessary in the 21st Century?" at the Brookings Institution in Washington, DC, on April 25, 2012. Rubio is a young, Latino, Tea Party-favorite from an important battleground state.
Marco Rubio
His inexperience on the national stage - he was elected to the Senate in 2010 - and questions about his details of his parents' immigration to the U.S. from Cuba could be potential drawbacks. In this photo, Romney speaks to the media before a town hall during a campaign stop with Rubio at Mustang Expediting on April 23, 2012, in Aston, Pa.
Kelly Ayotte
Sen. Kelly Ayotte, R-N.H., speaks during a press conference at the U.S. embassy in Manila on Jan. 17, 2012, while fellow senator John McCain listens. As former New Hampshire Attorney General, Ayotte could bring a law-and-order attitude to the Romney ticket.
Kelly Ayotte
But, Ayotte's not very experienced on the national stage - she was elected in 2010 - and political observers think that might remind voters of Sarah Palin. Romney and Ayotte are seen greeting supporters after delivering remarks regarding the shooting at a Colorado movie theater on July 20, 2012, in Bow, N.H.
John Thune
In this photo, Sen. John Thune, R-S.D., listens as Romney speaks during an appearance before employees at the Nationwide Insurance building on Nov. 23, 2011, in Des Moines, Iowa. Sen. Thune is telegenic, has years of experience in Washington and has been looked at as someone who could run for president himself one day.
John Thune
Even with all of his Washington experience, Thune is virtually unknown nationally, however. Thune is seen endorsing Romney during an appearance before employees at the Nationwide Insurance building on Nov. 23, 2011, in Des Moines, Iowa.
Bob McDonnell
In this photo, Romney listens as Gov. Bob McDonnell, R-Va., speaks during a campaign event at Crofton Industries, May 3, 2012, in Portsmouth, Va. McDonnell would be a hit with the conservative wing of the GOP and is popular in Virginia, an important battleground state.
Bob McDonnell
However, McDonnell's views on abortion - an issue which he's closely tied to - might be at odds with the views of women swing voters. In this photo, Romney arrives with McDonnell during a campaign event at the Electronic Instrumentation and Technology company on June 27, 2012, in Sterling, Va.