WASHINGTON – A plan that backers hope will give seniors greater choice in their health care under Medicare was unveiled by Sen. Olympia Snowe and other key lawmakers Wednesday.

They said they intend to hammer out legislation for a full Senate vote by mid-September.

The plan also calls for devising optional prescription drug programs aimed at cutting costs for seniors on needed medicine.

“There should be no mistake. We cannot truly claim to have modernized Medicare without prescription drug coverage,” Snowe told reporters during a Capitol Hill news conference.

Other key elements in the proposal call for establishing new sets of benefits with a fee-for-service plan that seniors could choose over the existing program. It also outlines the need to streamline medical regulations and strengthen rural Medicare service.

“This is just the beginning of a discussion,” said Snowe, a member of the Senate Finance Committee, which oversees Medicare. Other committee members, including Sen. Chuck Grassley, R-Iowa, the highest-ranking Republican on the committee, and Democrat John Breaux of Louisiana, joined Snowe in the announcement.

“Our road map captures the best of ideas that are already out there,” said Grassley.

To help pay for these changes, Snowe and Grassley took the lead in pushing a successful measure earlier this year that set aside $300 billion to help foot the bill on reforming Medicare and establishing a prescription drug program. The money can only be used if the Senate Finance Committee crafts a bill for a full Senate vote.

But engineering a program that will bring down drug costs may be the most contentious part of their plan.

Sen. Bob Graham, D-Fla., a leading senator on the issue, blasted the announcement as “a very dark chapter” because he believes any prescription drug program would need all $300 billion to keep costs affordable.

“They offered a plan that pumps billions into reorganizing the existing Medicare program into an almost unrecognizable form and, in the process, starves a potential prescription drug program out of existence.”

Graham’s bipartisan drug plan would require beneficiaries to pay just over $52 in monthly premiums. In exchange, the voluntary program would cover 50 percent of prescription drugs’ costs totaling $3,500 and pay 75 percent of costs between $3,500 and $4,000. Medicare would pay any drug expenses over $4,000 and the recipient would no longer have to foot any coinsurance costs.

The price tag on Graham’s proposal chalks in at around $318 billion for the coming decade, according to the Congressional Budget Office, the nonpartisan study group assigned to estimating costs of legislation.

Started in 1965, Medicare provides medical insurance to 40 million seniors and disabled Americans, but lacks assistance for purchasing costly prescription drugs unless a beneficiary is hospitalized. While an estimated two-thirds of those on Medicare receive drug benefits from private insurers and other sources, one-third goes without such coverage.

Snowe and her colleagues said they intend to include portions of Graham’s proposal into their own legislation, but offered few details about the costs. Nevertheless, they vowed to move forward with hopes of crafting a bill by mid-September.

Grassley said that they need to stick to that time frame because lawmakers in Congress will soon be eyeing the 2002 election year.

“No one wants to tinker with a popular but outdated program in an election year,” said Grassley. “Partisan politics will be the poison pill.”

Snowe expressed confidence that a measure could negotiated to embrace the best ideas offered by both Republicans and Democrats as well as the Vermont independent, Jim Jeffords.

“We think we can do just that,” she said.