BOSTON — Senator Kerry yesterday proposed requiring all Americans to have health insurance by 2012, “with the federal government guaranteeing that they have the means to afford it.”

The Democrat from Massachusetts, whose name is figuring prominently in 2008 White House speculation, repeated his 2004 presidential campaign call for expanding the federal Medicaid program to cover children.

He also proposed creating a program that would cover catastrophic cases so an employer providing insurance would not have to pass the cost to his other workers. The proposed program would also offer Americans the ability to buy into the same insurance program used by federal workers such as members of Congress.

Mr. Kerry proposes to pay for the program by repealing tax cuts enacted during the Bush administration that benefit those earning more than $200,000 annually. He did not immediately elaborate on how he would enact his insurance mandate, but one aid said he would do so with a requirement written into the legislation spelling out that the government covers anyone who is uninsured.

“One of my biggest regrets is that fear talk trumped the health care walk and that we are less safe abroad and less healthy at home because of that,” Mr. Kerry told a crowd of several hundred during a midday speech at Faneuil Hall. The senator had previously delivered two other speeches at the Revolutionary War meeting house, laying the groundwork for a second presidential campaign.

The senator also promoted his health care proposal in a Boston Globe op-ed piece published yesterday morning and during an appearance on Don Imus’s national radio program.

Mr. Kerry conceded his health care proposal is virtually the same as the program he outlined during his failed campaign. However, he said continuity was a measure of his commitment to his health care ideals.

“Every day since the election, the health care crisis has grown steadily worse,” Mr. Kerry said. “The president has stuck to his guns — or, more accurately, his empty holster — and done nothing beyond trotting out the conservative hobby horse of health savings accounts.”

The senator said his plan will lead to universal coverage by 2012, “but if we’re not there by 2012, we will require that all Americans have health insurance, with the federal government guaranteeing they have the means to afford it.”

The Republican National Committee, which typically responds to political criticism of the president, said Mr. Kerry’s critique ignored the prescription drug program enacted by the Bush administration.

“It’s unfortunate that John Kerry’s bitterness over losing the election clouds his ability to recognize the president’s prescription drug plan is providing millions of seniors with more affordable medicine,” an RNC spokeswoman, Tracey Schmitt, said.

Whatever his criticism, Mr. Kerry faces the reality that the Republican governor of his home state — Mitt Romney, himself a potential 2008 presidential candidate — has not only talked about but enacted a sweeping health care overhaul designed to bring universal coverage to Massachusetts. Last week, the secretary of the American Department of Health and Human Services, Michael Leavitt, called the program “a model” for the nation.

Mr. Romney negotiated the plan with a Democratic Legislature and in cooperation with Senator Kennedy, a Democrat of Massachusetts, who is Mr. Kerry’s senior colleague.

Under Mr. Romney’s plan, which the federal government is assisting with $385 million annually, Medicaid will be expanded for 100,000 people, the government will cover premium costs for another 200,000 who buy private programs, while an additional 200,000 will be required to buy insurance from low-cost policies offered by private companies working in tandem with the government.

Mr. Romney signed the bill into law in April on the same Faneuil Hall stage where Mr. Kerry planned his remarks.