A moratorium on new Medicaid rules that would save the states billions of dollars in reimbursements sailed through the House on a 349-62 vote last week, but the measure has met a familiar foe in the Senate: Sen. Tom Coburn (R-Okla.).

When Senate Majority Leader Harry Reid (D-Nev.) tried to fast-track the moratorium to the floor for a vote this week, Coburn stood in his way, saying that everyone knows that “states game Medicaid.”

The moratorium would postpone until 2009 the implementation of new Medicaid regulations that would otherwise take effect this June. The White House argues that the new regulations are needed to prevent waste, fraud and abuse in Medicaid.

But members on both sides of the aisle are wary because state governments back home can’t afford to lose Medicaid funding while they’re suffering from a sagging economy. Sen. Susan Collins (R-Maine) said that many of her colleagues are supporting the bill , as she is, out of loyalty to their home states.

Coburn seems to have different concerns; he argued that Congress shouldn’t buckle under the state pressure. “All we are willing to do as a body is say to the administration, ‘You have ideas that will get rid of $42 billion worth of fraud over five years, but we don’t like it because we are feeling pressure from the state Medicaid directors,’” he said.

Coburn told Reid Tuesday night that he would “work on trying to put together a proposal with the administration that would make a difference and then bring it to the floor.” He estimated the negotiations would take two weeks.

Senate Majority Whip Richard J. Durbin (D-Ill.) said the Democrats are “going to keep trying” to find a way around Coburn’s objections.

House Majority Leader Steny H. Hoyer (D-Md.) said the two chambers are working to send to the White House a package that will either get the president’s signature or have enough support to override a veto. “We’re still working on a compromise,” said Hoyer. “As you saw, we passed it overwhelmingly.”

Sen. Benjamin J. Cardin (D-Md.) said that at least a one-year moratorium is “clearly one of our top priorities.” He said that Democrats might attach a moratorium to “a bill that has to be signed.” He said the coming Iraq war supplemental was one such possibility.

A spokesman for Reid said that leadership was “still discussing how to proceed.”

Sen. Edward M. Kennedy (D-Mass.) said that he remains confident the bill will become law one way or another. “I think the merits of it are so overwhelming, and there’s an enormous amount of support. But it’s a sort of back-and-forth situation,” he said.

The effort to override a veto, however, could be complicated by Reid’s decision to bypass the Senate Finance Committee. Grassley, the ranking Republican on the committee, has called for the panel to rewrite the regulations rather than extend the moratorium. “The regulations do address areas where there are real problems in Medicaid,” he said on the floor in April. “Certainly there is reason to believe that states have been using case management to supplement state spending.”

Collins said it’s unclear whether Congress will be able to overturn a presidential veto, but she advised the White House to start talking and stop threatening. “I think the president would be well-advised to start negotiating rather than having a confrontation,” she said.