MERRILLVILLE, Indiana (AFP) - Hillary Clinton and Barack Obama skipped between Indiana and North Carolina, racing the clock ahead of Tuesday's fateful primaries which will shape the endgame of their tense White House duel.

The former first lady was cheered by new polls giving her a shot of staving off the Illinois Senator's latest attempt to knock her out of a race that threatens to split the Democratic Party.

Clinton, 60, started the day in North Carolina, where she is giving her rival a closer than expected race, before flying to midwestern Indiana, where she is seen to need a win to quell calls for her to quit the race.

"Think about who you believe, think about who you can count on," Clinton told supporters at a fire station here in one of Indiana's Chicago suburbs.

"If you go vote for me tomorrow, I will never forget you."

Obama was up at dawn in Indiana, at a construction site, canvassing the kind of blue-collar voters who have sided with the former first lady in past contests, and frustrated his attempts to clinch the nomination.

"This is going to be a tight election here in Indiana, every poll shows a dead heat, we need every single vote," he said, before later heading to North Carolina on another get-out-the-vote mission.

A new USA Today poll out Monday found that Obama, vowing to become America's first black president, had been damaged by the fallout of racially tinged remarks by his former pastor Jeremiah Wright.

For the first time in three months, the former first lady led her rival in the survey of national Democrats, by seven percentage points. Two weeks ago before the latest storm over Wright hit, Obama was up 10 points.

A CBS/New York Times poll on Sunday however suggested Obama had started to recover from the Wright furor, giving him an 11-point lead over Republican candidate John McCain, 51-40.

Last Tuesday, that hypothetical matchup had been tied. Clinton led McCain in the same poll by 12 points.

Another poll, by Suffolk University in Boston, Massachusetts showed the New York senator leading Obama in the rustbelt state by six points, 49 percent to 43 percent.

"It's no slam dunk, but Hillary Clinton is poised to win (Indiana)," said David Paleologos, director of the Suffolk University Political Research Center.

The two rivals meanwhile fought a vicious television advertising war.

"What's happened to Barack Obama?" asked a Clinton ad, focusing on his dismissal of her plan for a temporary moratorium in gasoline taxes, but also refering to his turmoil-wracked April.

Obama hit back with his own advert, accusing the former first lady of pandering over gas taxes, and playing the games of gridlocked Washington.

"What does Hillary Clinton offer us? More of the same old negative politics," the narrator of his ad said.

Obama, 46, who leads Clinton in pledged delegates and nominating contests won, seems to have a mathematical lock on the nomination but appeared resigned to battle on until the end of the primary calendar in June.

A Zogby tracking survey had the Illinois senator up by eight in North Carolina, a tighter gap than the 20 point lead he had enjoyed in some polls just weeks ago. Zogby had the race in Indiana a mathematical tie.

Clinton's camp admits she can't overhaul Obama in the count of pledged delegates who will formally anoint the nominee at the party convention in August.

So she is pinning her hopes on a collapse in Obama's support, hoping to convince party bosses, or superdelegates to conclude the Illinois senator cannot beat McCain in November.

Clinton's communications director Howard Wolfson predicted Tuesday's contests would show a "real tide" moving in her direction, arguing that the New York Senator had closed large polling deficits with Obama in both states.

AFP, May 5, 2008