A mortgage rescue plan to save hundreds of thousands of homeowners from foreclosure drew overwhelming Senate support, inching toward passage despite Republican objections.

The Senate voted 76-10 Monday to advance the bill, a broad array of housing measures including overhauls of the Federal Housing Administration, the Depression-era mortgage insurer, and government-sponsored home loan giants Fannie Mae and Freddie Mac.

Its centerpiece is a new $300 billion FHA program to allow debt-ridden homeowners who are currently too financially risky to qualify for government-backed loans to refinance into safer, more affordable mortgages.

The measure is on track for passage by an overwhelming margin, possibly by week's end. It has survived several test votes in the Senate, repeatedly demonstrating that there's enough support for it to override President Bush's promised veto.

But Sen. John Ensign, R-Nev., is blocking its progress because Democratic leaders have refused to allow a vote on attaching an $8 billion package of renewable energy tax breaks. Ensign has said he wants the tax incentives to hitch a ride on the housing measure because it has a good chance of being signed into law by Bush.

"This will be the major achievement and accomplishment of this Congress when it comes to dealing with the underlying economic crisis, which is at its heart the foreclosure crisis," said Sen. Christopher J. Dodd, D-Conn., the Banking Committee Chairman who wrote the legislation.

Beyond the Senate, the election-year package still faces a tricky path.

The president has said he thinks a deal is possible, but the White House is balking at key portions of the bill, particularly $3.9 billion included for buying and fixing up foreclosed properties. Democrats argue the money is key to preventing neighborhood blight, but most Republicans call it a bailout for lenders who helped cause the mortgage mess.

The two architects of the plan, Dodd and Rep. Barney Frank, D-Mass., the House Financial Services Committee Chairman, have been negotiating privately to iron out Democrats' differences on the plan, but the stalling tactics in the Senate have sapped momentum for a quick agreement.

One key divide is over limits on the mortgages FHA can insure and Fannie Mae and Freddie Mac can buy, which the Senate measure sets at $625,000. The House-passed bill set the caps at $725,000, which is preferable to lawmakers from the highest-cost housing markets, including Speaker Nancy Pelosi, D-Calif.

Also at issue is whether the new regulator and tightened rules for Fannie Mae and Freddie Mac should take effect immediately, as dictated by the Senate bill. The House-passed legislation delays them for six months, leaving it up to a new president to implement the changes.

And the two sides are at odds over which tax breaks to include and whether to pair them with offsetting tax increases to prevent a rise in the deficit — something that conservative "Blue Dog" Democrats insist on. The Senate's $14.5 billion package falls $2.4 billion short of being paid for, while the House's $11 billion is fully covered.

There is broad agreement on using the FHA to help struggling homeowners refinance into mortgages they can afford. The Bush administration has twice broadened the agency's authority to do so under a program it calls FHASecure. Top housing officials were planning to discuss the expansion — as well as the fate of the housing legislation — on Tuesday.