Nov. 11 (Bloomberg) -- Democratic presidential candidate Barack Obama said he would raise the cap on Social Security payroll taxes to fix what he called the single most important social program in the U.S.

Obama said he would be reluctant to back any plans for keeping Social Security solvent by cutting benefits or raising the retirement age.

``The best way to approach this is to adjust the cap on the payroll tax so that people like myself are paying a little bit more and the people who are in need are protected,'' Obama, an Illinois senator, said on NBC's ``Meet the Press'' program.

Obama, 46, who reported combined assets for him and his wife valued between $455,011 and $1.1 million last year, said those in ``the best position'' to protect Social Security should be tapped to do so and that would probably include, he said, a ``tax increase for people like myself.''

Obama was interviewed from Iowa, where he and the other main Democratic candidates were campaigning and giving speeches yesterday at the state party's annual Jefferson-Jackson Day dinner in Des Moines. The Iowa caucuses, traditionally the first contest in the nomination race, are scheduled for Jan. 3.

The 72-year-old federal Social Security program will begin taking in less in payroll taxes than it pays out to retirees in 2017, according to estimates by the program's trustees. Under the current system, only the first $97,500 of annual income is taxed. That limit is set to rise to $102,000 next year.

All Options

The Illinois senator hasn't specified exactly how he would overhaul Social Security, saying as president it would be important to ``look at all the options.''

Obama used the issue to draw a distinction between himself and his chief competitor for the Democratic nomination, Senator Hillary Clinton of New York.

Clinton, 60, hasn't spelled out a plan for keeping the system solvent for future retirees. She has said the system can be rescued by exercising ``fiscal responsibility.''

Obama said Clinton is running a ``textbook campaign'' by not tackling the tough issues, like Social Security, for fear that her answers ``might not be popular.''

``We're going to have to make some decisions, and it's not sufficient for us to just finesse the issue because we're worried that, well, we might be attacked for the various options we present,'' Obama said.

Clinton leads Obama in most national polls of Democratic voters and has an edge in Iowa and New Hampshire, which traditionally has held the first primary vote in the race. The results from Iowa and New Hampshire will probably shape the rest of the campaign.

Views of Clinton

Citing polls that show voters are strongly divided in their views of the former first lady, Obama said that Clinton would have a difficult time gaining a consensus for policy changes.

``I'm not somebody who believes that she can't win,'' Obama said. ``I believe that it's going to be harder for her to win.''

There are voters who have ``some preconceptions about her that are going to be very difficult to overcome,'' he said.

Clinton addressed that issue last night in Des Moines. She touted the support she's received from Democratic leaders in Republican-leaning states like Arkansas and swing states such as Ohio. They ``know that I can win,'' she said.

Obama said the first state primaries and caucuses are ``critical'' to his campaign for the nomination.

``We have to do well in Iowa,'' Obama said. ``I don't know a candidate out there who thinks that they can lose Iowa, new Hampshire, Nevada and South Carolina and still be successful.''

State Polls

In Iowa, a University of Iowa poll last month put Clinton's support among likely voters at 29 percent, 2 percentage points ahead of Obama. Former North Carolina senator John Edwards was third with 20 percent. A Boston Globe poll released today shows Clinton leading Obama 35 percent to 21 percent, with 48 percent of Democratic voters still undecided.

The New Hampshire poll also showed that 60 percent of Republicans are still undecided. Senator John McCain, while in third place, is in striking distance of former New York mayor Rudy Giuliani. Mitt Romney, a former Massachusetts governor leads with 32 percent, followed by Giuliani with 20 percent and McCain with 17 percent. The Arizona senator vowed today he would ``flat out'' win the state's primary.

``I can tell you right now I will win New Hampshire,'' McCain said on the ``Fox News Sunday'' program.

To contact the reporter on this story: Julianna Goldman in Washington at jgoldman6@bloomberg.net