Barack Obama, highlighting differences with John McCain on Social Security, declared yesterday that he would shore up the program by imposing payroll taxes on wages above $250,000 a year.

Now, the first $102,000 in salary is taxed at 6.2 percent. In specifically setting for the first time where he wants to apply further payroll taxes, Obama's proposal would create a so-called donut hole, because income between $102,000 and $250,000 wouldn't be taxed.

"Right now, the Social Security payroll tax is capped," Obama said in Columbus, Ohio, on day five of his economic tour of battleground states. "That means most middle-class families pay this tax on every dime they make, while millionaires and billionaires are only paying it on a very small percentage of their income. That's why I think the best way forward is to adjust the cap on the payroll tax so that people like me pay a little bit more and people in need are protected. That way we can extend the promise of Social Security without shifting the burden onto seniors."

Pledging to protect Social Security "today, tomorrow, and forever," Obama said 97 percent of Americans would not be affected by his plan.

He also hit McCain for being open to private savings accounts to supplement the retirement benefits, saying that amounts to privatizing Social Security.

McCain denied again yesterday that he supports privatization, though he has sounded open to the possibility in the past.

"I will not privatize Social Security, and it's not true when I'm accused of that," he said at a town hall meeting in New Jersey. "But I would like for younger workers, younger workers only, to have an opportunity to take a few of their tax dollars, a few of theirs, and maybe put it into an account with their name on it."

The McCain campaign also questioned the impact of Obama's tax proposals on seniors.

While Obama proposes to eliminate income taxes on seniors with less than $50,000 a year in income, McCain's campaign cited an analysis that Obama's plans would increase the tax bills for 10 million senior households, in part because of his proposal to raise capital gains taxes.

"Barack Obama likes to think that his tax increases will only hit a few Americans, but in truth his economic plan will be a disaster for everyone, especially seniors," Tucker Bounds, a McCain spokesman, said in a statement.

FOON RHEE

McCain, Obama tussle over town hall details

They both profess they want to do town hall meetings, but Republican John McCain and Democrat Barack Obama are in a stalemate over when, where, and how many.

In the latest tussling over town hall meetings, McCain yesterday accepted a proposal from the Ronald Reagan presidential library in Simi Valley, Calif., and the Lyndon Johnson presidential library in Austin, Texas, for town halls in July.