Many supporters of Barack Obama and Hillary Rodham Clinton are so divided they say they would rather cross party-lines and vote for Republican John McCain if their candidate does not win the Democratic nomination, according to a new poll. In a further boost to McCain, the former Arizona senator has erased Obama's 10-point advantage in a head-to-head presidential matchup, leaving him essentially tied with both Democrats, according to the Associated Press-Ipsos poll released Thursday. Between the two Democrats, the poll numbers were unchanged from February, with Obama at 46 percent and Clinton at 43 percent. However, the intense and extended Democratic primary race has turned off some Democrats. About a quarter of Obama supporters say they will vote for McCain if Clinton is the Democratic nominee. About a third of Clinton supporters say they would vote for McCain if it is Obama.Obama holds a lead in the race for delegates, and Clinton is hoping to revive her campaign with a win in the last major primary on April 22 in Pennsylvania, though it is doubtful she will catch up. Neither candidate will be able to clinch the 2,025 delegates needed to win the nomination without the approval of superdelegates elected officials and party insiders who also vote at the party's August convention. McCain is benefiting from a bounce in the polls since he essentially clinched the Republican nomination a month ago. The former Vietnam prisoner of war has slowly moved up in matchups with each of the Democratic candidates, particularly Obama. An AP-Ipsos poll taken in late February had Obama leading McCain 51-41 percent. The current survey, conducted April 7-9, had them at 45 percent each. Clinton led McCain, 48-43 percent, in February. The latest survey showed the New York senator with 48 percent support to McCain's 45 percent. Factoring in the poll's margin of error of 3.1 percentage points, Clinton and McCain are statistically tied. Obama campaigned Thursday in Indiana, which holds its primary May 6, while Clinton campaigned in Pennsylvania. McCain, meanwhile, was in New York, seeking to fend off criticism that he has been indifferent to the U.S. housing crisis and the weak economy. __
