The race for the Republican Party's 2016 presidential nomination includes 12 official candidates for the White House, while several others are likely to announce bids. Candidates are trying to stand out in a crowded field before the party's first debate in August featuring only the top 10 contenders.
Here is a list of the Republicans seeking the nomination or considering jumping into the race for the November 2016 election:
The former Florida governor, who is the brother of one president and son of another, formally announced his White House bid after long testing the waters. Before officially entering the race, Bush, 62, had already shaken up his staff and faced criticism for not distancing himself from the foreign policies of his brother, former President George W. Bush, and for struggling with questions about the invasion of Iraq. His moderate positions on immigration, education and other issues could make him less popular among many conservatives.
Retired neurosurgeon Carson, 63, is a favorite of conservative activists. He has played up his outsider status as a political neophyte, although he still lags in the polls. Raised in a poor family headed by a single mother, Carson rose to be director of pediatric neurosurgery at Johns Hopkins in Baltimore. He is the only black candidate running from either political party.
Cruz, 44, of Texas is the Tea Party favorite. He was blamed in some quarters for the October 2013 government shutdown because he wanted to link funding to repeal of President Barack Obama's healthcare law. The Harvard-educated son of a Cuban immigrant, Cruz was the first Republican to jump officially into the race and made an explicit appeal for Christian supporters.
Once one of the most powerful women in American business, the former Hewlett-Packard Co chief executive is positioning herself as an outsider with corporate experience.
But she was pushed out of the tech company and later ran a failed race for a U.S. Senate seat. Fiorina, 60, has criticized the only other woman so far seeking the presidency, Democrat Hillary Clinton.
The South Carolina senator, a close ally of 2008 Republican nominee John McCain, is running as a defense hawk on security issues and has made criticism of President Barack Obama's foreign policy the center of his campaign. A well-known face on Sunday U.S. news programs, the 59-year-old has been more moderate on other issues such as immigration reform and climate change.
Former Arkansas Governor Huckabee, 59, ran unsuccessfully in 2008 and declined to run in 2012 despite his popularity with influential evangelical leaders and voters. This time he consistently polls near the top of the pack, behind Bush. The former host of a popular Fox News television show has focused in public appearances on the plight of working Americans left behind in the economic recovery.
The former New York Governor, who led the heavily Democratic-leaning state for three terms, could be a moderate voice in a Republican field heavy with conservatives. Although he has not held public office since 2006 and lacks name recognition, Pataki, 69, has said his leadership during the Sept. 11, 2001, attacks in New York and Washington gave him insight into the current fight against Islamic State militants.
The first-term Kentucky senator, 52, is following his father, Ron Paul, in running for president. A libertarian, he has lobbed criticism at Democrats and fellow Republicans alike over the federal debt and personal liberties. He casts himself as an anti-establishment reformer who could win over young and minority voters. He drew recent ire from fellow conservatives for his role in trying to block a Senate vote on security legislation.
The longest-serving governor in Texas history crashed out of 2012's nominating process after an embarrassing debate performance in which he forgot a government agency he proposed to eliminate. But Perry, 65, has been preparing himself for a run in 2016 and promoting his state's economic growth.
Rubio, 44, cast his entry into the Republican field as a "generational choice." The son of Cuban immigrants, the U.S. senator from Florida decided to forgo a run for re-election in the key state. He was swept into the Senate in the Tea Party wave of 2010 but has fought to strengthen his ties with conservatives after he helped lead a failed push for comprehensive immigration reform in 2013.
A favorite of the Christian right, the former Pennsylvania senator, 57, won the Iowa caucuses in 2012 and was an active campaigner in the 2014 midterm election cycle. Bolstered in the past by social and religious conservatives, Santorum announced his 2016 bid with an eye on economic issues as other contenders also compete for Christian voters. He has promised to boost the middle-class, eliminate the Internal Revenue Service, push a flat tax and crack down on illegal immigration.
The 69-year-old real estate mogul and TV personality announced his candidacy from Trump Tower in New York, calling himself, if elected, "the greatest jobs president that God ever created." The outspoken billionaire is unlikely to ultimately win the nomination but will certainly enliven proceedings.
The New Jersey governor, 52, has fought hard to cultivate an image as a brash bipartisan dealmaker from a blue state. His potential candidacy suffered a setback with last year's "Bridgegate" scandal, but he has leveraged his status as head of the Republican Governors Association to gain support.
Louisiana's governor has made it clear he is eyeing a White House run. The former Rhodes scholar, 43, came under fire in early 2013 when he said Republicans needed to "stop being the stupid party." He has said he will announce whether he plans to run on June 24.
Walker, 47, won many conservative hearts in his first term as Wisconsin governor by cutting collective bargaining rights for public workers unions. He survived a 2012 recall election and won a second term in 2014. Though lacking the name recognition of some other potential candidates, Walker has the support of donors looking for a more conservative alternative to Bush.