Republican Mitt Romney suspended his faltering presidential campaign Thursday, effectively handing his party's nomination to John McCain and sealing an exceptional comeback for a politician who was considered all but washed up less than a year ago. Romney's decision leaves McCain as the top man standing in the Republican race, with Mike Huckabee far behind in the delegate hunt. It was a remarkable turnaround for McCain, a former Vietnam prisoner-of-war who some seven months ago was barely viable, out of cash and losing staff. The four-term Arizona senator, denied his party's nomination in 2000, was poised to succeed George W. Bush as the Republican standard-bearer. "If I fight on in my campaign, all the way to the convention, I would forestall the launch of a national campaign and make it more likely that Senator Clinton or Obama would win. And in this time of war, I simply cannot let my campaign, be a part of aiding a surrender to terror," Romney said in a speech to the Conservative Political Action Conference in Washington. Obama, riding a spectacular fundraising wave, announced Thursday that his presidential campaign had picked up $7.2 million since the first polls closed Tuesday, as his rival and former front-runner Clinton indicated she was struggling to keep up. In a sign of Obama's growing financial advantage, Clinton acknowledged Wednesday that she loaned her campaign $5 million late last month as Obama was outraising and outspending her heading into the Democrats' 22-state contests on Tuesday. Some senior staffers on her campaign also are voluntarily forgoing paychecks as the campaign heads into the next round of contests. While not matching Obama's pace, Clinton also saw an online surge of donations - raising $4 million from 35,000 new contributors since midnight Super Tuesday, Clinton campaign aides said. Clinton and Obama split wins in their "Super Tuesday" coast-to-coast contests. The mixed results tightened an already close race. Democrats have high hopes of winning the White House as the Republican Party has been closely associated by voters with the unpopular President George W. Bush. McCain's swept the races in California, New York and seven other US states. Mike Huckabee, a Baptist preacher and former governor of Arkansas, won contests in the South, where his appeal to Christian conservatives undermined Romney's support. Romney had 294 delegates, and Huckabee had 195. Clinton won in eight key races, including big prizes California and New York. But Obama kept up and gained momentum with wins in at least 13 of the 22 states that held Democratic contests Tuesday. Clinton had 1,045 delegates, to 960 for Obama, out of the 2,025 needed to secure victory at the party convention in August. Clinton's advantage is partly due to her lead among so-called superdelegates, members of Congress and other party leaders who are not selected in primaries and caucuses - and who are also free to change their minds. On Wednesday, Obama offered some pointed advice to superdelegates. He said if he winds up winning the most delegates in voting, they "would have to think long and hard about how they approach the nomination when the people they claim to represent have said, 'Obama's our guy."' Delegates still to be allocated included 25 in New Mexico, where Democratic voting remained too close to call. The southwestern state's Democrats were to begin examining more than 17,000 provisional ballots Thursday to determine a winner. Such ballots are given to voters who go to the wrong site or whose names are not on registered voter lists. Obama plans a campaign blitz through a series of states holding contests this weekend and will compete to win primaries in Maryland, Virginia, and the Washington, D.C. area next week and Hawaii and Wisconsin the following week. Clinton, with less money to spend, will instead concentrate on Ohio and Texas, large states with primaries March 4 and where polling shows her with a significant lead.