Washington ? Now for the hard part.

Even if the national credit card is maxed out and partisanship remains the rule for Washington’s political tribes, President Barack Obama and Congress are plunging ahead with a health care overhaul.

This week, Obama will start the dialogue on how to increase coverage, restrain costs and improve quality.

Whether a bill can get through Congress and to Obama this year is uncertain. For half a century, the track record on health care has been one of missed opportunities, spectacular failures and hard-won incremental gains.

Obama plans to stress the need for major changes in his address to Congress on Tuesday, administration officials say. He will follow up with a budget that includes a commitment to expand coverage for the uninsured. A White House summit on health care is being planned in coming weeks.

“They don’t intend to blink. They intend to plow ahead,” said health economist Len Nichols of the nonpartisan New America Foundation. “Health reform is seen as essential to balancing the federal budget and economic recovery in the long run.”

People in the U.S. spend $2.4 trillion a year on health care, or about $7,900 per person. That’s more than twice as much per capita as in other advanced countries. But few would claim those dollars are buying good value. The costs are a burden for taxpayers, employers and families, and the recession is leaving more people without insurance.

Yet even a self-described optimist such as Sen. Mike Enzi, R-Wyo., says he has doubts about prospects for overhauling health care. “It needs to be done up front and quickly,” said Enzi, the senior Republican on the Senate Health, Education, Labor and Pensions Committee. “I’m not so sure that we haven’t already lost that, with so many other things coming in and weighing us down.”

President Bill Clinton took the better part of a year to deliver a 1,300-page health care bill to Congress and later waved his veto pen at lawmakers who might have given him half a loaf. He got nothing. Obama has shown a tendency to be more pragmatic.

Administration and congressional officials say Obama will lay out a vision and see if Congress can make the details work. The Senate has gotten an early start and is shaping up as the proving ground for legislation.

“The Obama administration has said they are going to give the Senate a very wide berth,” said Sen. Ron Wyden, D-Ore., who for years has tried to get Democrats and Republicans working together.

Polls show most people support coverage for all and believe government should help guarantee it. But what looks like consensus starts to break down once thorny details such as costs and the government’s influence on the doctor-patient relationship come into the picture.

Administration officials say Obama has made a down payment by expanding coverage for children of low-income working families and by providing subsidies to help people who lose their jobs keep health benefits.

As he moves forward, Obama will follow the plan laid out in his campaign.

It calls for government, employers, families and individuals to keep sharing financial responsibility for health care. The approach would overhaul the health insurance market, particularly for self-employed people and small businesses. It would set up a national insurance purchasing “exchange” through which people would be guaranteed access to private health insurance or the choice of a new public plan.

Obama sees coverage for all as a goal to be reached in steps. His plan would not require every individual to purchase insurance. The estimated cost is about $90 billion a year, to start with.

The plan might sound simple in a brief summary, but it’s not. Potential dealbreakers lurk at every turn.

Many liberals can’t get excited about doing battle for just a promise — not an immediate guarantee — of coverage for all.

Conservatives and insurance companies fear that a public plan offered to workers and their families could become the gateway for Canada-style government health care for all.

Employers, hospitals, and drug companies worry that the government’s already pervasive influence in health care will become stifling.