

US Representative Michele Bachmann (R) of Minnesota addresses the Conservative Political Action Conference (CPAC) in Washington on Feb. 10. The prominent tea party politician announced, on June 13 during the second GOP presidential debate of the season, that she is indeed running for president. Larry Downing/Reuters
Former Republican vice presidential candidate and former Alaskan Gov. Sarah Palin says she is still deciding whether or not to run for president. Here she speaks at the Ronald Reagan Centennial celebration in Santa Barbara, Calif., on Feb. 4. Spencer Weiner/AP
Former Massachusetts Gov. Mitt Romney (R) speaks at the Conservative Political Action Conference (CPAC) in Washington on Feb. 11. Some say that 'RomneyCare,' the health-care plan he signed into law while governor, could derail his bid for the presidency.
New York City Mayor Michael Bloomberg delivers the fiscal year 2012 budget at City Hall in New York on Feb. 17. Mayor Bloomberg, said on Dec. 12 "I'm not going to run for president," but committee to draft him remains ardent in its hopes to persuade him. Fred R. Conrad/AP
Donald Trump waves after addressing the Conservative Political Action Conference (CPAC) in Washington, on Feb. 10. Trump said the main reason that he would run for president is that “the United States has become a whipping post for the rest of the world.” On May 16, he announced he would not run in the 2012 election. Alex Brandon/AP
On May 11, former House Speaker Newt Gingrich formally launched his presidential bid. Gingrich addresses the Conservative Political Action Conference (CPAC) in Washington on Feb. 10. The annual gathering of more than 11,000 conservatives marks the unofficial start of the GOP presidential nomination fight. Alex Brandon/AP
Louisiana Gov. Bobby Jindal (R) speaks to a joint legislative session in March 2010 in Baton Rouge, La. Despite repeated questioning, Mr. Jindal says that he has no plans to run for president. Tim Mueller/AP/File
US Representative Ron Paul (R) of Texas announced on May 12 that he was running for president again. Shown here, Paul speaks at the Conservative Political Action conference (CPAC) in Washington on Feb. 11, at which he won the straw poll for president. Jonathan Ernst/Reuters
New Jersey Gov. Chris Christie (R) speaks in Trenton, N.J., on Jan. 6. Although he has said there is "zero chance" that he will run for president in 2012, he tied for third in a straw poll at CPAC. Mel Evans/AP/File
Former New York mayor Rudy Giuliani speaks during a demonstration against Iran's President Mahmoud Ahmadinejad's appearance at the United Nations in New York in 2009. Mr. Giuliani is said to be considering another run at the presidency. Patrick Andrade/Reuters/File
Conservative radio host Herman Cain addresses the Conservative Political Action Conference (CPAC) in Washington on Feb. 11. The former CEO of Godfather's Pizza announced on May 21 that he was running for president. Jonathan Ernst/Reuters
Texas Gov. Rick Perry (R) delivers remarks at the Conservative Political Action Conference (CPAC) in Washington on Feb. 11.
Former US Ambassador to the United Nations John Bolton takes the stage to address the Conservative Political Action Conference (CPAC) in Washington on Feb. 12. Mr. Bolton is reportedly considering a presidential run. Jonathan Ernst/Reuters
Republican Mississippi Gov. Haley Barbour speaks at the Conservative Political Action Conference (CPAC) in Washington on Feb. 12. On April 25, Barbour released a statement saying he would not run, because he could not commit himself to the "all-consuming effort" required of a White House candidate. Cliff Owen/AP
Gov. Mitch Daniels (R) of Indiana speaks at the Conservative Political Action Conference (CPAC) in Washington on Feb. 11. Mr. Daniels announced May 22 that he would not run for president in 2012. Jose Luis Magana/AP
Sen. Jim DeMint (R) South Carolina speaks to the Values Voter Summit, held by the Family Research Council Action in Washington in Sept. 2010. Mr. DeMint's political advisers have indicated that he is entertaining the idea of a presidential bid. Jacquelyn Martin/AP
Then-Utah Governor Jon Huntsman (R) speaks to the White House press corps after being nominated US Ambassador to China in Washington in 2009. Huntsman resigned from the post, and has returned to the US, fueling speculation that he may run for president. On June 21, he announced his bid for the Republican presidential nomination. Yuri Gripas/Reuters/File
Former Sen. Rick Santorum (R) of Pennsylvania speaks at the Conservative Political Action Conference (CPAC) in Washington on Feb. 10. The senior fellow at The Ethics and Policy Center, radio-show host, contributor to Fox News, and newspaper columnist announced his candidacy on June 6. Larry Downing/Reuters
Former Arkansas Gov. Mike Huckabee (R) speaks in Washington in Sept. 2010. The Fox News host, author, and prolific public speaker considered the idea, but on May 14, Huckabee announced he would not run for president in 2012.
Former Minnesota Gov. Tim Pawlenty (R) gives the thumbs up after speaking at the Conservative Political Action Conference (CPAC) in Washington on Feb. 11. On May 22, the tea party supporter announced he would run for president in 2012. Alex Brandon/AP
Gary Johnson, former GOP governor of New Mexico, announced on April 21 that he will run be running for president. "I'm ready for a different America," Johnson said in a statement read from the steps of the New Hampshire State House. BusinessWire/File
Former Gov. George Pataki (R) of New York speaks at a ceremony at Ground Zero in memory of victims of the 9/11 terrorist attacks on Sept. 11, 2010 in New York. Mr. Pataki quit as chairman of Revere America, his anti-healthcare reform group, pointing to a possible presidential bid.