WASHINGTON – Blending conservative principles with political caution, key Republicans rallied yesterday behind a plan to introduce Social Security personal accounts on a more modest scale than President Bush favors.

“Our bill is the first bite at a bigger reform,” Rep. Sam Johnson, of Texas, said at a news conference. Several Republicans said the proposal may be brought to the House floor next month, possibly as part of a broader measure making changes in pensions and other retirement issues.

Democrats swiftly accused Republicans of mounting a fresh attempt to privatize the Depression-era program. “This is privatization, plain and simple,” said Rep. Sander Levin, a Democrat of Michigan. “Just like President Bush’s plan, this proposal would take money from Social Security to set up private accounts.”

In a blow to the White House, Republicans said their measure will not contain any of the politically painful cost-cutting steps needed to ensure long-term solvency for Social Security – higher taxes, an increase in the retirement age, or curbs in benefits.

Mr. Bush has made solvency and personal accounts financed from payroll taxes the twin goals of his call to overhaul the program. Despite an extensive nationwide campaign, he has failed to generate significant public support for his proposals.

Democrats are virtually united in their opposition and are preparing to use the issue in the 2006 midterm elections.

While Mr. Bush has called for using current payroll tax receipts to create a permanent new option for personal accounts, Republicans opted for a different approach.

And after weeks of bucking political headwinds, they said their proposal would strengthen Social Security. “It does stop the raid of the Social Security surplus,” said Rep. Clay Shaw, a Republican of Florida, echoing claims made by numerous Republicans.

Officials said that under the proposal, for an initial three-year period, surplus Social Security funds would be used to establish individual accounts for willing younger workers.The money would be in the form of “marketable Treasury bonds,” according to a written description, with the interest rate set by the government.

Unlike current law, according to Rep. Jim McCrery, a Republican of Louisiana, the effect would be to create a financial obligation to individual workers by name. He contrasted that to the current arrangement, which he described as the government promising, “We’re going to pay you these benefits, and we’re going to get them from somewhere.”

The GOP approach “effectively seals that money off for Social Security and just Social Security,” he said.

Officials said that for the initial three-year period at least, the Treasury would continue to make use of the surplus Social Security funds to pay for other programs – just as it has for years.

The legislation will establish an advisory board to recommend changes to Congress to take effect after three years, officials said.

Democrats argued that Republicans were making only a cosmetic change in Mr. Bush’s proposal. “One approach would create risky private accounts directly from a worker’s paycheck, and the other would finance risky private accounts from Social Security payroll taxes when they reached the federal Treasury,” said the House Democratic leader, Nancy Pelosi of California.

She said Democrats “stand ready to begin bipartisan discussions on protecting Social Security solvency, but this cannot begin until Republicans begin talking about ways to make Social Security stronger, not weaker.”

Whatever the reaction, the news conference marked a new phase in the congressional struggle over Social Security.

Four members of the House Ways and Means Committee, Messrs. McCrery, Shaw, Johnson, and Rep. Paul Ryan of Wisconsin, attended the news conference. So, too, did two conservative senators, one day before they plan to make an announcement on a companion Senate measure.

Rep. Bill Thomas, a Republican of California, the committee chairman, was intimately involved in drafting the bill, and House Majority Leader Tom DeLay issued a statement calling it a “positive first step toward strengthening retirement security for future generations.”

Ron Bonjean, a spokesman for the house speaker, Dennis Hastert, also called the proposal a good first step but declined to say whether the speaker would schedule the bill for a floor vote.

Mr. McCrery and others said it was possible the proposal would be combined with other measures Mr. Thomas is working on.