The House defied a presidential veto threat Wednesday and passed a bill intended to block gasoline price gouging.

Democratic leaders bypassed committee action to bring the bill (HR 1252) directly to the floor, where it passed 284-141.

The legislation, sponsored by Bart Stupak, D-Mich., would ban the sale of gasoline and other liquid fuels at prices that are “unconscionably excessive” when the president declares an “energy emergency.”

Such legislation would “lessen the pain that motorists are feeling every day when they fill up their cars at the gas pump,” Stupak said during floor debate on the measure, which split largely along party lines.

The bill was the latest in a flurry of activity aimed at addressing the recent spike in gasoline prices, which has received attention on Capitol Hill this week as lawmakers prepare to head back to their districts and face voters over the Memorial Day weekend, the unofficial start of the summer driving season.

On May 22, the House passed a bipartisan consumer protection bill (HR 2264) that would allow the Justice Department to sue members of the Organization of Petroleum Exporting Countries for colluding to set global oil prices.

Senate Democrats also sought to build support Wednesday for a broad energy package that Majority Leader Harry Reid, D-Nev., announced he plans to bring to the floor the second week in June.

That package will include price-gouging controls similar to those in the House-passed legislation, as well as a range of other provisions designed to decrease fossil fuel dependence. The Senate legislation also would require increased alternative-energy use and higher fuel economy standards for passenger vehicles.

House and Senate supporters of price-gouging legislation said such measures will provide motorists with short-term relief at the pump.

“It’s important that consumers have protections . . . to make sure that they aren’t being gouged by artificially manipulated prices,” Sen. Maria Cantwell, D-Wash., told reporters, adding that Democrats would not be cowed by a veto threat. “The only thing that needs to be vetoed is the notion that the oil companies should go unchecked.”

President Bush on Wednesday threatened to veto the price-gouging bill, which the administration warned “could result in gasoline price controls and in some cases bring back long gas lines reminiscent of the 1970s.” Oil companies have lodged similar protests.

Leading House Republicans also objected to the substance of the bill and to the fast-track procedures Democrats used to bring the legislation to the floor.

Joe L. Barton of Texas, ranking Republican on the Energy and Commerce Committee, argued that the bill would not adequately define price gouging. Barton urged lawmakers to send the measure back to committee to add language that would address supply issues.

“As demand goes up, if you don’t have the capacity to increase the supply, sooner or later the price is going to go up,” Barton said.

Stupak’s original bill would have applied gouging controls at all times, but the language was amended to cover only certain emergency situations. That aligns it more closely with language the Senate Commerce, Science and Transportation Committee approved earlier this month, which would ban price gouging whenever the president declares federal emergencies.

That language, part of a broader bill (S 357) to boost fuel efficiency standards, is expected to serve as part of the basis for the package that Reid wants to bring to the floor.

The House bill would grant the Federal Trade Commission authority to fine violators and seek criminal penalties of up to $150 million for corporations. For individuals, fines could reach $2 million, and prison time could reach 10 years.

“The oil companies have the consumers over a barrel — a barrel of oil that the oil companies control,” said Edward J. Markey, D-Mass., an Energy and Commerce Committee member who strongly favors the bill.

Last year, House Republicans passed a similar price-gouging bill, but the Senate did not act on it.

Wednesday’s bill passed under suspension of the rules, a procedure that limits debate, bars amendments and requires a two-thirds majority for passage.