GOP presidential candidates Ron Paul and Newt Gingrich think there's still a primary race on, but with Rick Santorum's April 10 exit from the Republican Party's 2012 presidential field, everyone else is turning attention to potential running mates for frontrunner Mitt Romney. It's all speculation at this point, but here (in alphabetical order) are 11 individuals who might make the cut:

Chris Christie (New Jersey)

New Jersey Gov. Chris Christie, 49, surprised many in 2009 when he won incumbent Democratic Gov. Jon Corzine's seat in the liberal-leaning state. Since then Christie has garnered national attention as he's worked with a Democratic-controlled legislature to pass fiscally responsible measures. Christie's record on social issues is mixed: He supports civil unions for homosexuals and nominated an openly gay man to serve on the New Jersey Supreme Court, but he also vetoed a measure to legalize same-sex marriage.

Mitch Daniels (Indiana)

Indiana Gov. Mitch Daniels, 62, formerly headed the Office of Management and Budget under President George W. Bush and was a senior adviser to President Reagan. His fiscal record has earned him a reputation as one of the Republican Party's leading budget experts. Daniels credentials also include passing stronger abortion regulations, creating a school voucher program, capping property taxes, and restricting the collective-bargaining power of public employee unions.

Luis Fortuno (Puerto Rico)

Puerto Rican Gov. Luis Fortuno, 51, may not be a household name yet, but he's considered a rising star in the GOP who offers a fiscally conservative record. Following his election in 2008, Fortuno immediately went to work reducing the territory's more than $3 billion deficit through budget cuts, the elimination of thousands of government jobs, and hefty tax cuts. Fortuno's Hispanic heritage would be an added plus for the presidential ticket.

Nikki Haley (South Carolina)

South Carolina Gov. Nikki Haley surged to victory in 2010 on a wave of Tea Party enthusiasm. Haley is the first woman and first minority-she's Indian American-to serve as governor in South Carolina. At 40, she's also the nation's youngest governor and less experienced than several of the other potential vice presidential picks. Her record thus far reflects conservative concerns, including passage of an immigration reform bill and a voter ID law.

Bobby Jindal (Louisiana)

Popular Louisiana Gov. Bobby Jindal, 40, would offer the presidential ticket racial diversity-he's the first Indian American to serve as governor-plus a record of spending cuts and deficit reduction. A conservative Catholic, he gained national attention for his leadership in the wake of the 2010 Gulf oil spill-positive press that helped erase some of the criticism he generated following his bumbled response to President Obama's 2009 address to a joint session of Congress.

Susana Martinez (New Mexico)

While New Mexico Gov. Susana Martinez's lack of experience leaves her in the un-vetted category, her presence could potentially give frontrunner Mitt Romney a boost with the female vote he has struggled to capture. Martinez, 52, is New Mexico's first female governor and the United States' first female Hispanic governor.

Bob McDonnell (Virginia)

Virginia Gov. Bob McDonnell-a former Army officer, attorney general, and state legislator-hails from a Southern swing state where his term will soon expire. McDonnell, 57, is considered a social conservative but his resume took a hit earlier this year after he pressured legislators to soften an ultrasound bill he had previously vowed to sign.

Tim Pawlenty (Minnesota)

Former Minnesota Gov. and presidential candidate Tim Pawlenty, 51, has years of governmental experience-including a decade in the Minnesota House-and a strong record on domestic policy during his eight years in the governor's mansion of a historically Democratic state. He ended his first term as governor by successfully reducing the more than $4 billion deficit and balancing the budget without raising taxes.

Rob Portman (Ohio)

U.S. Sen. Rob Portman's resume includes stints as former President George W. Bush's director of the Office of Management and Budget and as Bush's U.S. Trade Representative. Portman, 56, who also served seven terms in the U.S. House, was a member of the 2011 bipartisan "supercommittee" that failed to agree on $1.2 trillion in deficit cuts. His residence in a key swing state gives him an edge.

Marco Rubio (Florida)

First-term U.S. Sen. Marco Rubio, 40, could add balancing elements to Romney's frontrunner ticket with his status as a Tea Party favorite and his background as the son of Cuban immigrants. Rubio is relatively inexperienced, but he hails from a key swing state, where he notably beat moderate Charlie Crist in 2010. The father of four young children is a practicing Catholic who also attends a Southern Baptist church and as a child belonged to the Mormon Church.