Washington ? Reminding Americans of his commitment to Medicare reform, President Bush called on Congress on Wednesday to “finish the work” of passing a prescription drug bill.

“After years of debate and deadlock, the Congress is on the verge of Medicare reform,” Bush said.

The president’s speech to an invited audience at the Dwight D. Eisenhower Executive Office Building was punctuated with well-worn arguments for modernizing the 38-year-old program that covers health care for 40 million Americans.

But with House-Senate negotiations all but stalled over the question of how to reform Medicare while covering prescription drugs rather than whether to do so, many said Bush’s remarks would do nothing to move the process forward.

White House officials have signaled in recent days that while passage of a Medicare prescription drug benefit is important to Bush, whose public approval ratings on domestic issues have been slipping, the details of the legislation are not.

Yet it is the specifics of the Medicare legislation — particularly its limited coverage of seniors’ drug expenses, an emphasis on health-maintenance and preferred-provider organizations and a $400-billion, 10-year price tag — that has spurred growing opposition to the legislation.

The libertarian Cato Institute, the National Taxpayers Union and the Alliance for Retired Americans are among the groups that in recent days have begun running advertisements, writing letters to congressional leaders and issuing statements saying, in essence, that “no bill is better than a bad bill.”

Bush promised during his 2000 presidential campaign to make prescription drug coverage for seniors one of his top priorities. With Republicans controlling both houses of Congress, many GOP lawmakers also feel the pressure to deliver on a promise before next year’s election campaigns get under way.

“I urge the Congress to act quickly, to act this year, not to push this responsibility to the future,” Bush said. “We have the opportunity; we have the obligation to give seniors more choices and better benefits.”

Members of the conference committee working to forge a compromise between the House and Senate bills passed in June said Wednesday that they still had not resolved issues concerning competition between traditional Medicare and private health plans, efforts to control Medicare spending, the importation of U.S.-made drugs from Canada and health savings accounts.