NEW YORK — The tightness of the race between President Bush and Democrat John Kerry — neck-and-neck in national polls — is causing anxiety among some of Bush’s staunchest supporters in South Carolina.

They’re hoping the president’s acceptance speech tonight before the Republican National Convention will give the campaign some kind of boost.

“He could lose the election,” says convention delegate and state Sen. Mike Fair, R-Greenville, adding quickly, “not in South Carolina.”

“It’s the old thing about the economy. If it doesn’t continue to grow, he could have problems. A surge before the election certainly would help. People also are tiring of the war.”

Recent surveys have shown the war and security could trump the economy in this election.

With persistent violence and climbing casualties, the aftermath of the war in Iraq has become a problem for Bush, turning what once was believed to be an asset for re-election into a vulnerability.

Only about four in 10 Americans support the president’s handling of Iraq, polls show, and just one-third believe he has a clear plan to deal with the situation.

South Carolina delegates say Bush’s speech tonight is critical.

“He needs to draw a sharp contrast between himself and Kerry,” says Glen O’Connell, a Pawleys Island delegate.

But House Speaker David Wilkins of Greenville, chairman of the Bush-Cheney campaign in South Carolina, rejected the notion this is a make-or-break speech for Bush.

“This presents the president with a good opportunity to lay out his agenda for the next four years and to let voters know what his vision is for the country,” he says. “He can proudly stand on his record.”

Delegates look for Bush to begin to pull away from Kerry after Labor Day, when experts say voters will start to focus on the presidential contest.

“When people go into that booth on Election Day, they are going to pick who they trust with their future,” says delegate Shell Suber of Columbia, chairman of the Richland County GOP.

South Carolina is considered safe for Bush. It has backed a Democrat for president only twice in the past 44 years. What worries S.C. Republicans is how the president will fare outside the reliably Republican South.

“It’s going to be close,” says delegate Mark Hartley of Mount Pleasant, a member of the state GOP executive committee. “I disagree with those who say someone is going to win big. I don’t see it that way.”

Republicans were encouraged Kerry showed little movement in head-to-head polls after July’s Democratic National Convention in Boston.

Supporters hope Bush’s address tonight will influence the electorate. A key for the president after the convention will be regaining an advantage in the intensity of support.

If that happens, says Spartanburg delegate Michael Dixon, “we’ll have momentum going into the election.”

Gov. Mark Sanford is more cautious.

“In the world of politics, it’s not over until the fat lady sings,” he says. “It’s a very good possibility that Bush could lose. Anybody who says everything is perfectly fine is not being realistic.

“At the end of the day, Bush will probably prevail — but the margins are going to be tight.”