Washington ? President Bush is readying a new budget that would carve savings from Medicaid and other benefit programs, congressional aides and lobbyists say, but it is unclear if he will be able to push the plan through the Republican-run Congress.

White House officials are not saying what Bush’s $2.5 trillion 2006 budget will propose saving from such programs, which comprise the biggest and fastest-growing part.

But lobbyists and lawmakers’ aides, speaking on condition of anonymity, said he would focus on Medicaid, the health-care program for low-income and disabled people. Medicaid costs are split between Washington and the states.

Many expect him to propose giving states more flexibility in using the $180 billion in federal Medicaid funds each year, but to limit the program’s growth on a per-patient basis — in effect forcing the states to find ways to save money.

Bush also may propose trimming doctors’ reimbursements or weeding fraud from Medicare, the health insurance system for the elderly and disabled.

He may seek savings from agriculture and other benefit programs as well in the spending blueprint he will send to Capitol Hill on Feb. 7.

President Bush talks with his father, former President George H.W. Bush, left, during the 55th Presidential Inaugural Prayer Service at Washington's National Cathedral. First lady Laura Bush and daughters Barbara Bush, partially hidden, and Jenna Bush, right, also attended Friday's service. President Bush turned from inaugural pageantry to a daunting second-term agenda Friday.

There has not been a serious effort to pluck savings from such programs — called entitlements because the benefits go automatically to anyone who qualifies — since 1997.

After two straight record federal deficits that peaked at $412 billion last year, many Republicans are eager to constrain government spending by curbing the growth of benefits. By law such programs, which consume nearly two-thirds of the budget, grow to keep pace with inflation and ever-larger numbers of recipients.

Conservatives may want to go even further than whatever savings Bush proposes. Many of them consider Bush’s goal of halving the budget deficit by 2009 too timid, and see the coming retirement of the 76 million baby boomers as threatening to snowball federal spending.