WASHINGTON – President Bush outlined his Medicare reform plans and promised quicker relief for high prescription drug costs Thursday, but Sen. Susan Collins, R-Maine, warned that his proposals may be shot down by Democrats who want to deny him a legislative triumph.

“There may be some on the other side of the aisle who would prefer to keep the president from having a victory on this issue,” Collins said shortly after joining fellow Republican Sen. Olympia Snowe of Maine for a meeting with Bush at the White House. “I hope that won’t be the case.”

Speaking in the Rose Garden while surrounded by elderly Americans and lawmakers, the president outlined a “first step” prescription drug discount plan and an eventual broad overhaul of the 36-year-old government health care program.

Collins and Snowe spoke with the president in a meeting in the Roosevelt Room before the ceremony.

“The president knows that this issue is extremely important to seniors in Maine,” Collins said. “Every weekend, inevitably a senior comes up to me and tells me a sad story about the enormous burdens of the cost of prescription drugs.”

At the meeting, Snowe thanked the president for what her spokesman called “his leadership role on what will be a challenging debate.”

Under Bush’s Prescription Drug Discount Program, Medicare would endorse and promote several privately administered prescription drug discount cards, like those currently offered by pharmaceutical and other companies. The cards would be free or cost no more than $25. The White House estimates the card could save Medicare recipients 25 percent in typical medicine purchases, or as much as 50 percent for mail-order drugs. The proposal does not require action by Congress.

“It would give immediate help to seniors,” Collins said. “I don’t see that as a substitute for a Medicare prescription drug benefit, but it’s a step that could be implemented quickly.”

Bush also outlined several requirements for legislation aimed at a Medicare overhaul that would include better coverage for checkups and serious ailments. Seniors already enrolled in Medicare and those near retirement must have the option of keeping their Medicare the way it is today, he said. And all seniors must be offered a range of new Medicare plans, including an updated government plan, as well as private insurance plans, all of which must offer coverage of prescription drug costs. The goal is to have the plans compete with each other to offer better service, extra benefits and lower premiums. Finally, all plans must put a loss limit on the amount any senior can be asked to pay in a given year.

While there is broad support on Capitol Hill for the concept behind a prescription drug benefit, Bush’s proposals are likely to face legislative obstacles from Republicans as well as Democrats.

“There may be some Republicans who believe that we cannot afford to have a full-scale benefit to all seniors, and who only want it for very low-income seniors,” Collins said. “Benefits under Medicare have traditionally been universal, a position which I support. However, we may be able to adjust the amount of premiums, based on income.”

“Our strong desire is to pass a meaningful prescription drug benefit,” Senate Majority Leader Tom Daschle, D-S.D., told reporters. “We’re going to be putting this legislation on a fast track, and we are encouraged by the extraordinary interest that there appears to be among groups for this legislation, too. So we welcome his interest, but I hope he’s prepared to go a lot farther than simply providing this redundant discount.”

The Senate Finance Committee is expected to take up the issue later this month. Collins predicts that the full Senate will vote on the issue in September, and will “hopefully” have a bill before the president before the end of the year.

“It’s unclear whether Democrats are going to work with or against the president,” Collins said.

Interest groups had a mixed reaction to Bush’s proposals. Karen Ignagni, president of the American Association of Health Plans, a trade organization representing more than 1,000 health maintenance organizations, praised Bush’s “bold vision.”

Richard Clark, president of Merck-Medco, the largest prescription drug provider in the country, said he and his company look forward to participating in the program. Merck-Medco manages 450 million prescriptions per year for its clients through 12 mail service pharmacies and retail pharmacy networks.

“The program, while not a substitute for Medicare drug coverage, will give seniors better information and access to drug discount programs that can save them money and improve their health,” Clark said in a statement.

But representatives of chain drugstores panned the plan.

“Independent studies have proven the fallacy of state-based prescription discount card programs for seniors,” said Craig L. Fuller, president of the National Association of Chain Drug Stores and former chief of staff for ex-President George Bush when he served as vice president. “They don’t work. The same fallacies are likely to occur with a national discount card program.”

In addition to Collins and Snowe, Bush invited Sens. John Breaux, D-La., and recent GOP defector James Jeffords, an independent of Vermont, to the ceremony. He thanked members of “all three political parties” for attending.