Under the administration's math, GOP aides said, the plan represents $4.6 trillion in 10-year savings. That estimate accounts for earlier cuts enacted during last year's showdown over lifting the government's borrowing cap and also factors in war savings and lower interest payments on the $16.4 trillion national debt.Last week, the White House delivered to Capitol Hill its opening proposal: $1.6 trillion in higher taxes over a decade, a possible extension of the temporary Social Security payroll tax cut and heightened presidential power to raise the national debt limit. In exchange, the president would back $600 billion in spending cuts, including $350 billion from Medicare and other health programs. But he also wants $200 billion in new spending for jobless benefits, public works projects and aid for struggling homeowners. His proposal for raising the ceiling on government borrowing would make it virtually impossible for Congress to block him going forward. Republicans said they responded in closed-door meetings with laughter and disbelief. The GOP plan is certain to whip up opposition from Democrats opposed to any action now on Social Security, whose defenders say should not be part of any fiscal cliff deal. And Democrats also are deeply skeptical of raising the Medicare age. Both ideas were part of negotiations between Boehner and Obama in the summer of last year. In a letter to the president, Boehner and six other House Republicans insisted that the November election that returned Obama to the White House and the GOP to majority control in the House requires both parties to come together "on a fair middle ground." "With the fiscal cliff nearing, our priority remains finding a reasonable solution that can pass both the House and Senate, and be signed into law in the next couple of weeks," Republicans wrote. One of the few things the White House and Capitol Hill Republicans can agree to is a framework that would make a "down payment" on the deficit and extend all or most of the expiring Bush-era tax cuts but leave most of the legislative grunt work until next year.