Both chambers are expected to defy the White House on Tuesday and pass legislation that would require the administration to halt oil shipments to the Strategic Petroleum Reserve (SPR).

The strong bipartisan support represents a major shift for Republicans, who until now have generally followed the lead of President Bush in contending that halting deliveries would have almost no effect on gasoline prices.

Democrats have long opposed pumping more oil into the reserve when gasoline prices are high, arguing that it pushes prices even higher, and that diverting the fuel into the market could ease some pain at the pump.

Bush has threatened to veto the proposal if it crosses his desk, but some lawmakers say support is so strong that it may pass both chambers with enough votes to override a veto.

The Senate is expected to vote on the proposal to halt those shipments as an amendment to a flood insurance bill (S2284). The prospect of passage in the Senate prompted House leaders to add a stand-alone bill (HR 6022) to the Tuesday floor vote schedule.

The Senate measure would bar deliveries to the reserve as long as the price of crude oil remains above $75 per barrel. That idea was proposed as part of a larger energy package introduced last week by Senate Democrats (S 2991); it’s similar to a provision in a larger Republican energy package (S 2958) also scheduled for a Tuesday vote.

In the House, Speaker Nancy Pelosi, D-Calif., and Energy and Commerce Chairman John D. Dingell, D-Mich., have pushed hard in recent weeks to freeze SPR shipments, calling repeatedly on Bush to halt the oil deliveries.

In recent days, Republican House members have also indicated their support. The bill will be considered under suspension of the rules, which bars amendments, limits debate and requires a two-thirds majority vote for passage.

‘There’s wide bipartisan support for it,” said a House Democratic leadership aide. “Otherwise, we wouldn’t put it on under suspension.”

On Sunday, Minority Whip Roy Blunt, R-Mo., told CNN that he would “like to see us do something about the Strategic Petroleum Reserve. I think we should stop filling it.”

In every other way, the Senate Democratic and GOP energy packages are different, composed of a grab bag of recycled provisions that have long been passionately opposed by the other side, and many of which have failed repeatedly in previous Congresses.

But by breaking off this piece of their broader energy package, Democrats appear to be setting up a political victory that would allow them to claim credit for moving oil legislation.

“Solutions to our energy problems came up in a very partisan manner. What we’re trying to do with this provision is salvage something that can be done, that’s constructive. If it works, maybe we can build on it,” said Jeff Bingaman, D-N.M., chairman of the Senate Energy and Natural Resources Committee.

Bingaman added that one reason the measure has drawn bipartisan support is that, of all the pieces of both packages, it is probably the most modest and limited. Even the measure’s chief advocate, Democratic Sen. Byron L. Dorgan of North Dakota, called it a small first step, rather than a fundamental solution to high gasoline prices.

“It’s the first baby step in the right direction. We need to do a number of things, but at least this is something we agree on,” said Dorgan. “We’re doing it because we believe it can get done.”

The measure also has won widespread support from industry. Timothy Lynch, senior vice president of Federation Relations and Strategic Planning for the American Trucking Associations, said Monday that any new fuel in the market could help truckers cope with the cost of diesel, which has soared so high it costs $1,200 to fill a truck tank. “Trucks can’t stop buying fuel, but the government can,” he said.

White House spokeswoman Dana Perino said Monday that President Bush still opposes the move and in fact wants to expand the size of the reserve.