In the short run, congressional leaders have achieved their goal of producing an agreement Sunday on a federal bailout of banks and other financial institutions holding bad mortgage debts before the world’s stock markets reopened.

But in the long run, the scope and still-unknown effects of the greatest government intervention in the financial markets since the Great Depression – and the remaining underlying instability of the nation’s economy – will impose a new political challenge for the next president and Congress elected in November. The situation already has reshaped the election campaign debate.

Congressional leaders face another immediate and uncertain challenge this week – with the House expected to vote on the plan as soon as today and the Senate as soon as Wednesday – in corralling enough votes to both pass it and present the controversial two-stage bailout as a bipartisan response to a national crisis.

While resistant House Republican leaders have agreed to it, many rank and file members still are balking at the unprecedented bailout of the nation’s financial institutions, piling as much as $700 billion of new federal debt on the nation’s taxpayers.

Congressional leaders are attempting to frame the measure as their own best compromise on a plan that the Bush administration proposed which they are now calling unacceptable.

This means, in part, dividing the bailout into two phases, starting with $350 billion but requiring congressional approval for a second payout. And it includes a demand that if the government does not recoup all the money that it invests in reselling mortgage debt that it purchases, it comes up with a plan to get the financial industry to cover any projected taxpayer losses.

“This is the administration’s problem,” House Speaker Nancy Pelosi, D-Calif., said Sunday. “They sent us their bill, we did our best to improve it, and now we’ll see how much support we can get. : We will have to have bipartisanship to pass it.”

President Bush, who proposed the Treasury Department rescue and has pushed for it with national television and radio addresses, calls it essential to averting “financial panic” in frozen lending and a “long and painful recession. Congressional leaders agree that it is essential in averting a freeze in credit for everything from home loans and car loans to student loans and credit cards.

“Getting this done soon, promptly, is absolutely critical to the confidence of the markets,” Sen. Judd Gregg, R-N.H., one of the lead negotiators, said Sunday, predicting the votes to approve it this week. “The option of not passing it is not acceptable.”