President Bush has heard pleas for an extension of the deadline to sign up for new Medicare drug coverage from lawmakers, seniors advocacy groups and finally two women in his audience Tuesday. He's rejected them all.

"Deadlines are important," the president said at a retirement community, less than a week before the last day for most seniors and the disabled to enroll in the program without facing higher prices. "Deadlines help people understand there's finality and people need to get after it."

The new program allows 43 million Medicare beneficiaries to enroll in a private plan that will subsidize the cost of their prescription medications. With about 37 million people now either signed up or automatically enrolled, federal officials from Bush on down have engaged in an all-out push to spread the word to those remaining and help them navigate the Byzantine process of choosing a plan by Monday.

"We want people to understand there are really good benefits," the president said. "If you haven't looked at the program, take a look."

Bush's aggressive promotion of the Medicare benefit — and his refusal to push back the deadline — is likely about politics as much as policy.

The White House and congressional Republicans are hoping that the glitches of the program's early days and the confusing signup process will have faded to a distant memory by the fall midterm elections, replaced by widespread satisfaction with having help from Medicare with prescription drug costs for the first time.

As the controlling party in Congress, Republicans hope seniors — who play an outsize role in non-presidential elections — will give them credit in the voting booth for enacting a popular new benefit.

For now, though polls show most who enroll are happy with the insurance, many seniors and those trying to help them still are complaining about the program's complexity. Most people have more than 40 plans to select from, and savings vary depending on the medicines needed, income levels and the plan chosen.

On a three-day, three-city tour through the state with the highest percentage of senior citizens, Bush urged seniors to press through those concerns.

"I did know that there would be some worries about having to choose from 40 different plans," he said. "But I thought it was worth it because I know that 40 different plans here in Florida will mean that individual can tailor a plan to meet his or her needs."

The president invited questions, and one woman told him a last-minute rush has created logjams on the Internet and over the phone.

Bush held fast, though he emphasized that poor seniors are exempt from the penalties the deadline brings for others.

He also defended the government's efforts during the signup period, particularly among the hard-to-reach low-income population. Julie Goon, director of Medicare outreach for the Department of Health and Human Services, estimated that half of the nearly 6 million people who have not yet enrolled fall in that category.

The activist group Families USA released a report Tuesday showing that less than a quarter of those eligible for the program's low-income subsidies have enrolled. "There are millions of seniors who need drug coverage and are not receiving it," said Families USA executive director Ron Pollack,

Bush's stop in the Tampa area followed an appearance earlier in the day near Fort Lauderdale. There, he visited Broward Community College, where government officials set up tents and tables with laptops to guide dozens of seniors through plans. Bush mingled among those waiting in a courtyard where Frank Sinatra's "Young At Heart" played on loudspeakers.

On Wednesday, he holds a Medicare-promotion event in Orlando.