WASHINGTON — President Barack Obama would not sign a Senate bill introduced Tuesday that would approve the Keystone XL oil pipeline, his spokesman said, as a top Democratic supporter urged the administration to seek a compromise.

A bill to sidestep an agency review was the first legislation Republicans introduced as they took control of the House and Senate for the first time since 2007. The measure has enough sponsors to pass but not enough to override a veto.

“My office has reached out to the White House today,” Sen. Joe Manchin, a West Virginia Democrat and a bill co-sponsor, told reporters in Washington on Tuesday. “We’re looking at ways that we can work together to find out if there are some areas that they might, on content, object to that we can work with.”

Given widespread public and industry support for the Keystone pipeline, Manchin said he was optimistic that Obama, who has expressed doubts about the project’s benefits, can be persuaded not to veto the measure.

At the White House on Tuesday, Press Secretary Josh Earnest said that if the Keystone bill passes Congress, the president wouldn’t sign it. Earnest said the measure introduced Tuesday is “not altogether different from legislation that was introduced in the last Congress” and was opposed by Obama, he said.

Republicans hold 54 of the Senate’s 100 seats, and many if not all nine Democrats who backed a Keystone bill in November are again likely to support the measure, giving it enough votes to pass. The House will vote on a similar Keystone bill Friday.

Sen. John Hoeven, a North Dakota Republican and the bill’s chief sponsor, said 60 senators are backing his measure and three others have said they probably would support it. That’s four votes shy of the 67 needed to override a presidential veto.

Should Obama issue a veto, supporters may seek to attach it to another piece of legislation that may pass, such as a government funding bill, Hoeven said.

“We’ll see what he does, but I think it really raises the question: Is the president going to work with Congress?” he said.

Government agencies are funded through the end of the fiscal year on Sept. 30, except for the Department of Homeland Security, which lapses at the end of February.

TransCanada Corp. proposed Keystone in 2008 to carry oil sands from Alberta across Montana, South Dakota and Nebraska toward U.S. refineries along the Gulf of Mexico coast. It’s been held up in a political feud over jobs, climate change and energy prices. A State Department review is in limbo, pending resolution of a legal dispute over the route in Nebraska.

“TransCanada is greatly encouraged by the introduction of bipartisan legislation in the new U.S. Congress and the support of lawmakers who continue to make Keystone XL a legislative priority,” CEO Russ Girling said in a statement.

Democratic Senate leaders opposed to circumventing the review are planning to offer amendments that would ban the export of any crude oil transported through the U.S. over the pipeline and require American-made iron, steel and manufactured goods be used in the pipeline’s construction and maintenance.

The Republican-controlled House has the votes to easily pass its Keystone bill this week. The question is whether Congress could muster the two-thirds votes to override a veto if Obama rejected the measure.

“The bill will pass and any veto will be sustained,” David Goldston, director of government affairs at the Natural Resources Defense Council, told reporters. “We don’t foresee anything changing that.”

Hoeven said an initial procedural vote on his measure would take place Jan. 12 and that the chamber would spend “several weeks” on the bill considering a range of amendments.

“Instead of a veto threat, the president should be joining with Congress on a bipartisan basis,” Hoeven said.

New Senate Majority Leader Mitch McConnell, a Kentucky Republican and staunch Keystone supporter, has pledged to allow both parties wide latitude to offer amendments to bills, including the pipeline measure.

Obama has criticized arguments that Keystone is an economic boon. At a year-end news conference Dec. 19, he said Keystone will be “very good for Canadian oil companies, and it’s good for the Canadian oil industry, but it’s not going to be a huge benefit to U.S. consumers. It’s not even going to be a nominal benefit to U.S. consumers.”