US President George W Bush has vowed to push through big reforms to the Social Security programme in his next term.
Mr Bush was speaking to a friendly audience
"Now is the time to work together to confront the problem... the crisis is now," he told business executives and economists at the White House.
Mr Bush is proposing part-privatisation of the state pension fund, which will come under increasing pressure as baby-boomers retire.
Democrats, unions and groups for the elderly are opposed to the plans.
Mr Bush also vowed to cut the ballooning deficit, and overhaul the tax code and legal liability system.
Mr Bush set out his agenda for his second four-year term on the final day of the two-day White House Conference on the Economy.
"One of the things that we heard today from experts was that the Social Security system is safe today, but is in serious danger as we head down the road of the 21st century," Mr Bush told a supportive audience of economists and business executives.
As the post-war generation of baby-boomers retire, and as people live longer, economists and demographers have calculated the Social Security system, which now takes in more than it pays out, will turn over to making net payments.
Mr Bush says he did not believe raising taxes is the right way to confront the problem. He proposes workers be allowed to take part of the Social Security taxes they currently pay and instead invest in private accounts.
Mr Bush said there would be "reasonable guidelines" set to insure people would not be able to "take [the money]
to Vegas and shoot dice".
He noted that politicians who talk about changing Social Security "get clobbered for it politically" but reminded his audience - and Congress - the issue had been part of the campaign platform on which he had been re-elected.
But Democrats, labour unions and groups for the elderly are passionately opposed to what is seen as the first step to dismantling the Depression-era retirement programme.
"The president's economic summit should have been an opportunity to begin an honest discussion about strengthening and improving Social Security," said House Democratic Leader Nancy Pelosi and Senate Democratic Leader Harry Reid in a joint statement.
"We cannot support any plan that relies on massive and irresponsible increases in debt, which could destabilize financial markets and lead to large tax increases," they said.
Democrats argue the plan will require yet more borrowing
Democrats argue that the plan could cost $1 trillion over the next 10 years to implement - a shortfall that will have to be covered with more borrowing.
The AARP, a group that represents Americans over 50, conceded "some changes need to be made" but said Social Security should be strengthened, not replaced.
"Private accounts are expensive," it said in a statement on its website. "Some critics of these personal accounts think that Wall Street, not retirees, would be the real beneficiaries.
"Now that Social Security has moved to the top of the political agenda, we must all work together to protect it," it said.