FACTBOX: Profiles of presidential hopefuls

(Reuters) - Following are brief profiles of the three presidential contenders:

DEMOCRATS:

HILLARY CLINTON, 60, has nationwide name recognition as the wife of former President Bill Clinton. A senator from New York who would be the first woman president, Clinton revived her campaign by sweeping critical popular vote showdowns in Ohio and Texas on March 4 after losing 12 straight contests to rival Barack Obama. On Tuesday, her victory in Pennsylvania again helped keep her campaign alive, although she still faces a nearly insurmountable lead in delegates to the nominating convention. Clinton has focused recent campaign efforts on her national security experience and emphasizes efforts to insure 47 million Americans without health insurance. She has criticized Obama for not having enough experience to lead the nation.

BARACK OBAMA, 46, had appeared headed for victory after his long winning streak until the losses in Ohio and Pennsylvania. But due to the way delegates are rewarded for the Democrats, Obama still holds a lead over Clinton in the overall delegate count. Obama, who would be the first black president, gained national recognition when he gave the keynote address at the 2004 Democratic convention before he was elected to the U.S. Senate. A first-term senator from Illinois, Obama has opposed the Iraq war from the beginning and portrays himself as a Washington outsider who has attracted huge campaign crowds cheering his message of the need for change in the country.

REPUBLICAN:

JOHN MCCAIN, 71, a senator from Arizona, clinched the Republican nomination after four big victories on March 4. The wins forced his last major rival, former Arkansas Gov. Mike Huckabee, out of the race and gave McCain more than the 1,191 delegates needed to win the nomination. The U.S. Naval Academy graduate and Navy pilot spent 5 1/2 years as a prisoner of war in Vietnam. McCain, who turns 72 in August, would be the oldest first-term president. He has been a pro-business conservative and abortion foe, while supporting the Iraq war and calling for extra troops to quell the violence. He says he has the best national security credentials of any of the presidential hopefuls.

(Writing by Deborah Charles; Editing by Doina Chiacu)

(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)