WASHINGTON – The Senate failed Wednesday to override President Obama's veto of Keystone XL pipeline legislation, ending for now attempts by Congress to speed up approval of the controversial energy project.

Falling short of the two-thirds majority needed, Republican backers of the pipeline could not peel off enough Democratic supporters to join them. The vote was 62-37, with all Republicans and eight Democrats in favor.

The outcome was the latest setback for the GOP-led Congress, which made passage of Keystone a top priority.

"For a long time, projects like Keystone used to be no-brainers — they were often approved without much controversy at all," said Senate Majority Leader Mitch McConnell, R-Ky., who made the bill the first order of business when he took control of the chamber in January.

"But that was before powerful special interest groups and ideological extremists decided to embark on a quixotic quest."

Democratic opponents said halting the project was the right decision. Critics of the pipeline argue it would prolong energy dependence on fossil fuels and worsen climate change.

"Why would we build a pipeline to bring filthy, dirty oil to our great nation, to our communities?" asked Sen. Barbara Boxer, D-Calif. "The only thing it helps, frankly, are the special interests in Canada."

With the outcome in the Senate, rules prevent the House from taking its own override vote.