WASHINGTON -- With the Social Security debate stalled in the Senate, a key Republican senator yesterday said President Bush must lay out a more specific plan to address Social Security's long-term solvency if legislation is going to move forward.

Sen. Lindsey Graham, R-S.C., who has been among the most active in seeking a compromise with Democrats, said Bush must expand beyond his proposal to allow younger workers to open individual investment accounts carved out of their Social Security taxes.

There have been few signs that the deadlock will be broken anytime soon. Senate Minority Leader Harry Reid, D-Nev., has said Democrats will not negotiate on Social Security until the individual investment accounts that Bush has proposed are off the table -- and so far, no Senate Democrat has broken ranks.

Graham said he believed that individual accounts could become more "meaningful" after lawmakers have found a solution for the program's projected $4 trillion shortfall over 75 years.

He said the Democrats' opposition to any form of individual investment accounts within Social Security has allowed them to "hide behind concepts" and avoid addressing specific legislation. If the president were to come forward with a specific solution for the shortfall, Graham said, Democrats would be forced to enter the debate.

"The president has laid out his principles for reforming Social Security, and we look forward to working with Congress to come up with a plan," White House spokesman Allen K. Abney said yesterday, adding that Bush has madeclear that he welcomes ideas from any member of Congress willing to take part in the debate.

Beginning in 2017, there will be less revenue coming into the Social Security system from taxes than the amount needed to pay Social Security benefits to recipients.

Even Bush has acknowledged that individual investment accounts do not address Social Security's solvency; in fact, the cost of the transition to a system that includes individual accounts could reach more than $1 trillion.

"In the current environment, nobody's going to negotiate," Graham said. "A date certain for a vote would be the best thing that could happen. There are a lot of senators and congressman hoping this goes away, but if you set a date certain, ... I think you're going to get moving. Combine that with a more specific proposal by the president, [and] I think you start negotiations."

Sen. Chuck Grassley, R-Iowa, who heads the Senate panel that would oversee any Social Security legislation, agreed that the president needed to talk more about long-term solvency within Social Security, but said that task must also be shouldered by members of Congress.

"We have not pushed enough discussion of solvency," Grassley said. "You lay every fact about Social Security out -- about its insolvency -- and you're not going to have Democrats and Republicans disagree. They might disagree about when to do something about it, or how to solve that red ink, but we need to be concentrating on that, and we haven't done that."

Grassley said his goal was to have a Social Security measure drafted by this summer, and he wants to build the legislation from the ground up with his committee's members.