Under the normal rules of politics, Congressional Republicans ought to be doing victory laps these days because of the new Medicare drug benefit, accepting the gratitude of the nation's retirees.

Instead, at meetings around the country, they are trying to ease widespread confusion and apprehension about a program that strikes many retirees as dauntingly complex. At a forum in Louisville, Ky., last week, Representative Anne M. Northup, a Republican, tried to reassure about 300 intensely attentive retirees. "I encourage you not to be discouraged," Ms. Northup said, soothingly. "If you feel like you don't know where to go, please call my office."

Beyond altruistic concerns, Congressional Republicans have a keen political interest in ensuring an orderly, successful rollout of the program, which happens to begin in a highly competitive midterm election year. The drug benefits are available for the first time beginning Jan. 1, and the initial sign-up period, which began Nov. 15, lasts until May 15.

Nobody knows how popular the drug benefit will ultimately be with the nation's retirees, who are a critical voting bloc. But Congressional Republicans, who pushed through the Medicare drug law in 2003, have clear political ownership of it, and whatever credit or blame it brings, strategists say.

Glen Bolger, a Republican pollster, said his advice was simple: "It's going to be associated with Republicans, so you better make sure it's something they understand and take advantage of."

Already, many Democratic strategists argue that the new program - because of its complicated structure and gaps in coverage - could be much more of a problem than an asset for Republicans next year. Some Democratic challengers are already using the issue on the campaign trail, like Christopher S. Murphy, who hopes to unseat Representative Nancy L. Johnson of Connecticut, a senior Republican who played an important role in writing the law.

"Seniors, frustrated with the complexity of the drug benefit, are realizing that it was constructed to help the insurance industry and the drug industry," said Mr. Murphy, a state senator, in a common Democratic refrain. "It's more helpful to those industries than to a lot of seniors."

Celinda Lake, a Democratic pollster, said the idea that the new law prohibited the government from negotiating lower prices with drug companies was particularly unpopular with retirees. And, Ms. Lake added, older baby boomer women - presumably trying to figure out the plan for their parents - react negatively to its complexity.

Republicans counter that, properly explained, the drug benefit is a huge advantage to the 42 million Americans on Medicare - the biggest expansion of the program since its creation 40 years ago.

"Establishing the drug program was a compassionate thing to do," said Representative Phil Gingrey, a Georgia Republican and doctor who heads a health care task force for House Republicans. "President Clinton and Congressional Democrats were unable to do it."

Mr. Gingrey, who has held more than 40 town hall meetings on Medicare in the last few years, added: "If the new program works, and we truly believe it will, we should see less diabetes, less kidney failure, fewer strokes, and we could save money in other parts of Medicare. That's the political message. We should be able to win this argument."

Even so, Democrats, and some Republicans, are already pushing legislation to extend the May deadline for signing up for the drug benefit without penalty. They argue that retirees need more time to decide what to do and more flexibility to change their minds. The penalty for a late sign-up is significant - an increase in premiums of 1 percent for every month past the deadline.

"Seniors are confused, bewildered and frightened," said Senator Bill Nelson, Democrat of Florida, who is leading the push for a delay. 

The administration is opposed to such delays, arguing they are unnecessary and would only compound the uncertainty about the program.

Representative Michael G. Fitzpatrick, a freshman Republican from suburban Philadelphia, said that after a dozen town hall meetings in his district, "what I heard, universally, from my senior constituents was, 'We need more time.' "

The Medicare drug plan was devised to reflect central Republican tenets: that private companies, and private market forces, are the best way to deliver drug benefits to the nation's elderly; that the government's role should be sharply limited, particularly when it comes to exerting price pressure on the drug companies; and that the nation's retirees ought to have a full array of options for their drug coverage.

In fact, Medicare beneficiaries have many more choices than officials had expected. In Kentucky and Illinois, for example, they can choose from 42 free-standing prescription drug plans, with different premiums, deductibles, co-payments and lists of covered drugs. Many recipients say they simply feel overwhelmed.

"So many choices!" said Virginia R. Potempa, 80, after a Medicare forum held last week by Representative Judy Biggert, a Republican, in Bolingbrook, Ill., outside Chicago. "The government seems to think everybody works a computer. Well, we do not."

Still, Mrs. Potempa, who spends $300 a month for six prescription drugs, said she intended to enroll in the plan. "We are very concerned," she said. "We need coverage. We need insurance."

Mrs. Biggert said she was confident that retirees were becoming more familiar and comfortable with the plan. But Representative Jan Schakowsky, Democrat of Illinois, said she held a meeting on Medicare last week that ended with a constituent standing up and declaring, "This is just ridiculous."

Ms. Schakowsky said frustration with the drug benefit reminded her of the anger that forced Congress to repeal a 1988 law covering catastrophic medical expenses under Medicare. At the time, she was executive director of the Illinois Council of Senior Citizens, whose members chased after Dan Rostenkowski, then the chairman of the House Ways and Means Committee and a principal author of that law, in what became an iconic image of popular uprising against an out-of-touch Congress.

Ms. Schakowsky warned that Republicans "better go out and buy some running shoes, because angry senior citizens will be after them." 

Representative Anthony Weiner, Democrat of New York, said he was stunned by the turnout at two meetings he held last week - more than 400 people at a session in Brooklyn, and 700 in Queens. Like many other Democrats, Mr. Weiner opposed the bill but said he wanted to help his constituents figure out "how they can benefit from a program that's inefficient and impractical."

Republicans angrily respond that Democrats have sought partisan advantage on the drug issue from the start - often heedless of what it might mean for retirees who could in fact be helped by the program. Representative Northup, after her meeting in Louisville last week, said, "It's been so disheartening for me to see the Democrats almost hope bad things will happen so they can gain some political advantage."

Robert Blendon, an expert at Harvard on public opinion and health, said he believed the drug program would become a major factor in next year's elections only if so many retirees became so anxious that they failed to sign up - and then suddenly faced a penalty for doing so. 

But Democrats clearly see the drug benefit as part of a broader message about the influence of special interests in a Republican-controlled Congress, arguing that Republicans were far more concerned about protecting the profits of the drug and insurance industry than delivering real coverage to beneficiaries. Moreover, some Democratic strategists said, Republicans are also vulnerable among retirees because of President Bush's failed effort to partly privatize Social Security, and because of ethical scandals rocking the party.

Representative Rahm Emanuel of Illinois, chairman of the Democratic Congressional Campaign Committee, scoffed at the idea that the drug benefit would help Republicans at all. "It's a loser for seniors, it's a loser for taxpayers on the political front, and it's an example that there's a cost to this corruption," he said.

Mr. Emanuel added that he doubted a single Republican in a competitive race would feature the drug benefit in television advertising.

Representative Johnson, in Connecticut, said she planned to. "Absolutely, without question," she said. "It's a wonderful benefit."

Mrs. Johnson predicted that the new Medicare law would follow the course of the 1996 welfare law. After the welfare law took effect, following years of impassioned debate, she said, it was widely accepted as a major improvement in social policy.