WASHINGTON — President Obama rejected an attempt by lawmakers to force his hand on the Keystone XL oil pipeline, using his veto pen Tuesday to sweep aside one of the first major challenges to his authority by the new Republican Congress.
With no fanfare and a 104-word letter to the Senate, Obama vetoed legislation to authorize construction of a 1,179-mile pipeline that would carry 800,000 barrels of heavy petroleum a day from the oil sands of Alberta to ports and refineries on the Gulf Coast.
In exercising the unique power of the Oval Office for only the third time since his election in 2008, Obama accused lawmakers of seeking to circumvent the administration's approval process for the pipeline by cutting short "consideration of issues that could bear on our national interest."
By rejecting the legislation, Obama retains the right to make a final judgment on the pipeline on his own timeline. But he did little to calm the political debate over Keystone, which has become a symbol of the continuing struggle between environmentalists and conservatives.
Backers of the pipeline denounced Obama's actions and vowed to keep fighting for its construction.
The House speaker, John A. Boehner of Ohio, called the president's veto "a national embarrassment" and accused Obama of being "too close to environmental extremists" and "too invested in left-fringe politics."
Environmentalists quickly hailed the decision, which they said clearly indicated Obama's intention to reject the pipeline's construction. The White House has said the president will decide whether to allow the pipeline when all of the environmental reviews are completed in the coming weeks.
"Republicans in Congress continued to waste everyone's time with a bill destined to go nowhere, just to satisfy the agenda of their big oil allies," said Michael Brune, executive director of the Sierra Club.
Since 2011, the proposed Keystone pipeline has emerged as a broader symbol of the partisan political clash over energy, climate change and the economy.
Most energy policy experts say the project will have a minimal impact on jobs and climate. But Republicans insist that the pipeline will increase employment by linking the United States to an energy supply from a friendly neighbor. Environmentalists say it will contribute to ecological destruction and damaging climate change.
Obama has hinted that he thinks both sides have inflated their arguments, but he has not said what he will decide.
In his State of the Union address last month, Obama urged lawmakers to move past the pipeline debate, calling for passage of a comprehensive infrastructure plan. "Let's set our sights higher than a single oil pipeline," he said.
Republican leaders had promised to use the veto, which was expected, to denounce Obama as a partisan obstructionist. They made good on that promise minutes after the president's veto message was read on the floor of the Senate on Tuesday.
"The fact he vetoed the bipartisan Keystone pipeline in private shows how out of step he is with the priorities of the American people, who overwhelmingly support this vital jobs and infrastructure project," Reince Priebus, the chairman of the Republican National Committee, said in a statement.
The debate began in 2008, when TransCanada Corp. applied for a permit to construct the 1,179-mile pipeline.
The State Department is required to determine whether the pipeline is in the national interest, but the last word on whether the project will go forward ultimately rests with the president.