The Biden administration’s decision to waive sanctions on a Russian-built pipeline in Europe keeps hitting close to home.

The move to let the pipeline go forward, which drew bipartisan criticism at the time, not only kicked off the Republican-led blockade of President Joe Biden’s foreign-policy nominees — now it’s imperiling passage of the annual defense policy bill, typically a bipartisan affair that’s become law each year for six decades.

GOP senators have resorted to hardball tactics to force the administration to implement sanctions on the Russia-to-Germany natural gas line, known as Nord Stream 2. Republicans have slow-walked confirmation of key national security officials and, on Monday night, blocked further action on the defense policy bill absent a vote to strengthen those sanctions.

Passing the defense bill and working to confirm as many of the 50-plus nominees as possible are just two priorities on the Senate’s year-end to-do list. But both goals are at risk of failure — and the whole problem originates with Nord Stream 2.

“We’ve tried everything with the administration to try to get this done, and they won’t do it,” Sen. Jim Risch of Idaho, the top Republican on the Foreign Relations Committee, said in a brief interview. “So I don’t know what you do with somebody when they won’t follow the law. You gotta keep hammering that, and that’s what we’re doing.”

Risch is among a handful of Republicans who objected to a package of amendments to the defense bill because it didn’t include his proposal to impose sanctions on Nord Stream 2 AG, the company heading the project, and allow Congress to override presidential waiver authority. A similar provision was included in the House-passed defense bill.

Republicans believe that considering the provision would force Democrats to take a politically difficult vote against the Biden administration, which waived the sanctions this year in a bid to preserve the U.S.-Germany relationship and trans-Atlantic unity. The German government supports the pipeline because it will deliver cheap energy to the country, but the U.S. and its western partners believe that the project will jeopardize Europe’s energy security by strengthening Russian leader Vladimir Putin.

Earlier Monday, Senate Minority Leader Mitch McConnell cited the pipeline as a reason he would vote against cutting off debate on the annual defense bill, which typically clears both chambers with overwhelming bipartisan support. McConnell made his move after Republicans had rejected an agreement to vote on a slate of 19 amendments, many of them GOP-authored.

“Considering sanctions on the pipeline that fuels Putin’s encroachment over Europe, including provisions from Sen. Risch, that closely mirror language that the House added unanimously, is certainly worth the Senate’s time,” McConnell said on the Senate floor before announcing he would vote against advancing the defense policy bill.

The chamber ultimately failed to secure an agreement on cutting off debate Monday night, leaving the legislation without a clear path forward. Democrats — and the White House — accused Republicans of hijacking the process for political gain.

“We’re seeing some members of Congress press for sanctions that don’t actually deter Russia but do threaten Transatlantic unity, in order to score political points at home — all while holding up critical national security funding on a range of unrelated issues,” a White House official told POLITICO in a statement. “It makes no sense.”

“I think the Republicans should stand by their always-motto that we must protect the troops, we must do everything possible, and we can’t let anything stand in its way. That’s what I’ve always heard,” Senate Foreign Relations Committee Chair Bob Menendez (D-N.J.) said. “It’s time to put up or shut up.”

Sen. Tim Kaine (D-Va.), a member of the Armed Services and Foreign Relations panels, said he believes Republicans are trying to make things more difficult for Democratic leaders, who are tasked with shepherding the defense bill, Biden’s social spending package, a debt ceiling increase and other critical measures through the chamber before the end of the year.

“They want to kill [the social-spending bill], so if they can slow everything else down, that’s probably what they’re trying to do. I wouldn’t have thought they’d try to do that with the defense bill,” Kaine said. “I think they’re just trying to make everything hard at year-end.”

But Republicans countered that Senate Majority Leader Chuck Schumer delayed full consideration of the defense bill until this month, even though it cleared the Armed Services Committee in July.

“Let me be clear — Sen. Schumer has put us in this position today. He waited more than two months after we filed the NDAA to bring it to the floor,” Sen. Jim Inhofe of Oklahoma, the top Republican on the Armed Services panel, said on the floor. “Because the majority leader mismanaged the Senate schedule, he won’t allow votes on bipartisan amendments that make our country more secure.”

The hangup puts leaders of the House and Senate Armed Services committees, who must deliver a compromise defense bill to Biden’s desk by the end of 2021, in a bind. Even if Democrats and Republicans can pass a bill in the coming days, committee leaders will have just a few weeks to iron out a final bill.

Committee staff have been hashing out differences in their competing bills for weeks already in an effort to smooth over the talks. And lawmakers have said that, to save time, they may resort to methods outside of a formal conference committee to negotiate and pass a compromise bill.

State Department leaders, meanwhile — including energy security adviser Amos Hochstein — have urged congressional leaders to take steps that would prevent Nord Stream 2-related sanctions from being included in the defense bill, according to two people familiar with the outreach. That includes stripping the Nord Stream 2 provision from the House-passed NDAA when the two chambers’ bills are reconciled later.

A senior State Department official characterized the conversations as part of the “regular order of business” when Congress considers measures that the administration might find objectionable.

The official said Risch’s amendment would tie up the Senate floor with votes on individual sanctions every 90 days. The House’s language is “completely unprecedented,” the official said, because it would remove the president’s waiver authority.

“Of course we’re going to express our opinion, as the administration and as the State Department, to say that we would never agree to losing our ability to make foreign policy and use sanctions as a tool,” the official said.

Still, Democrats are rejecting the suggestion that they’re afraid of voting on Risch’s amendment or any other provision related to Nord Stream 2.

“I’ve never been one to whisper in the leader’s ear asking that I not have to vote on something,” Sen. Brian Schatz (D-Hawaii) said. “That’s the job.”

So far, Democratic leaders are showing no signs of caving to the GOP demands, including on the pipeline.

“The Republican choice to block our bill — and by extension legislation to support our troops and protect the homeland — can be summed up in two words: inexplicable and outrageous,” Schumer said. “I hope the American people are watching.”