WASHINGTON – Congressional leaders dug in Sunday for a lengthy battle over the nation’s solvency as lawmakers determine how much debt the Treasury can accumulate and whether to reform the expensive entitlement programs of Medicare and Medicaid.

After two weeks of sometimes tumultuous meetings with constituents at home, lawmakers return to the Capitol’s fiscal wars this week. They must consider whether to raise the federal debt ceiling beyond $14.3 trillion in exchange for still undefined budget-tightening reforms — a debate that is certain to linger well past the preliminary deadline of May 16. That delay has already prompted Treasury Secretary Timothy Geithner to use accounting moves that would allow the United States to continue to make payments without exceeding the debt ceiling. But he would run out of possibilities in early July.

Setting the stage for prolonged negotiations, Democrats and Republicans criticized one another Sunday over which reforms to attach to legislation extending the debt limit, with Democrats adamant that higher taxes on the wealthy and revoked tax privileges for oil companies be a part of a broad deficit-reduction package. Most Republicans refuse to consider higher taxes as part of any final deal and demand the focus be on slashing entitlement spending.

“A lot of people think this is sort of like the magic fairy dust of budgets, that we can just make a small amount of people pay some more taxes and it will fix all of our problems. Well, let’s keep our eye on the ball. The eye on the ball is spending. And the sooner we get this thing under control, the better off everybody is going to be,” House Budget Committee Chairman Paul Ryan, R-Wis., said on ABC News’ “This Week With Christiane Amanpour.”

“The idea that we should come up with a balanced deficit reduction plan is right. But what’s wrong is to say that if one side doesn’t get 100 percent of what it wants in terms of coming up with that plan that they will put the entire economy at risk,” Rep. Chris Van Hollen, D-Md., the top Democrat on the budget panel, countered on CNN’s “State of the Union.”

Neither the House nor the Senate is considering legislation this week that is considered serious, with each body taking up proposals that are designed to score political points. Instead, the most critical action is happening behind closed doors at both ends of Pennsylvania Avenue.