This post has been updated

Senate Democrats stalled the Republican-led push to construct the Keystone XL Pipeline on Monday, dealing the first significant blow to the new Republican majority less than three weeks after being sworn in.

The outcome handed at least a temporary victory to some Democrats and environmentalists, who staunchly oppose construction of the pipeline. But Monday’s vote was more a speed bump than a roadblock; both parties are expected to continue hashing out their differences on the bill.

The measure fell short of attaining the 60 votes needed to proceed to final passage under Senate rules. Fifty-three senators voted to move to a final vote on the oil pipeline, which would run from Canada to the U.S. Gulf Coast, while 39 voted against it.

The vote fell mostly along party lines. While a handful of centrist Democrats crossed over to vote with the GOP, others withheld their support in protest against Republican leaders, who they say unfairly ended consideration of proposed amendments last week.

Eight senators were absent from the vote, including Minority Leader Harry M. Reid (D-Nev.), who was recovering from eye surgery; Sen. Marco Rubio (R-Fla.), who is on a fundraising swing as he weighs a White House run; and Sen. John McCain (R-Ariz.), who was traveling to Saudi Arabia to pay respects to late King Abdullah.

President Obama has said he will veto the bill if it gets to his desk. But now, it’s unclear how soon it could reach him, as both parties must continue negotiating in order to advance the bill.

If Republicans aren’t able to move forward on the bill by the end of the week, it could put the GOP push to construct the pipeline in serious jeopardy.

While Republicans have pitched the plan as a job-creator, Democrats have warned of adverse environmental effects and repeatedly cited a State Department report indicating the pipeline would create only 35 permanent jobs.

“Most McDonald’s” franchises offer more jobs, said Sen. Richard J. Durbin (Ill.), the second-ranking Democrat. He repeatedly called Keystone XL a “Canadian” pipeline.

Monday’s vote came after a contentious process in which some two dozen Republican and Democratic amendments were offered.

Democrats complained that Majority Leader Mitch McConnell (R-Ky.) didn’t live up to his pledge of an open process when he opted not to hold votes on some of their amendments late last week. McConnell countered that his amendment process has been far more open than it was when Democrats controlled the Senate.

“All in all the last few weeks have been time well spent,” McConnell said on the Senate floor as the chamber opened the week Monday afternoon.

After the vote, McConnell said he would have the Senate reconsider the measure.

The House passed a similar but less sweeping Keystone bill earlier this month. That bill passed with less than two-thirds support, meaning Democrats probably have the votes to prevent Republicans from overriding a presidential veto, should the bill make it to Obama’s desk.

While the Senate was in session, the House canceled its Monday votes, citing a blizzard bearing down on the Northeast.