"I would anticipate that, as we've been saying for years, the president would veto that legislation," Obama spokesman Josh Earnest told a press briefing.
"And he will."
The Republican-controlled Congress passed the legislation earlier this month, and plans to send it to the president Tuesday. The president then has 10 days to send it back to Congress unsigned — which constitutes a veto.
Earnest said that's exactly what the president will do. And he'll do it quietly, without a public event.
"I would not anticipate a lot of drama or fanfare."
The announcement is a blow to the pipeline's prospects, but not quite a fatal one. The big Keystone XL decision could come soon, in a separate regulatory process controlled by the president.
Obama has repeatedly said it's not Congress's role to approve or reject cross-border infrastructure. The White House says courts have consistently declared that the constitutional responsibility for that belongs to the president, and that the process was most recently spelled out in a 2004 executive order signed by George W. Bush.
The years-long, oft-delayed process is expected to wrap up soon, though the White House has not set a deadline date.
Members of Congress have also mused that if the president both vetoes the pipeline bill and rejects the project through the regulatory process, they'll come back with another Keystone XL bill that attaches the pipeline to omnibus legislation that the president will be tempted to sign.
Polls show a plurality of Americans support the project.
The sponsor of the Keystone bill announced it would be sent to Obama on Tuesday. Republicans could have sent it a week earlier, before lawmakers left Washington for a one-week recess. But they decided to hold off until this week, forcing Obama to make his decision with his opponents back in town.
"The administration has delayed this important infrastructure project for over six years, despite a series of environmental reviews, all of which conclude that the project will have no significant environmental impact," said a statement from North Dakota Republican Sen. John Hoeven.
"It has been more than enough time to make a fair decision on the merits of the project... The will of the American people and Congress is clear. I encourage the president to sign this legislation."
Hoeven issued that statement Monday morning. The White House responded with its veto announcement just after noon.