The U.S. Senate failed to advance an annual bill Monday that authorizes construction of defense infrastructure, including the type of ships built at Bath Iron Works.

Sixty Senators needed to vote to open debate on its version of the National Defense Authorization Act, but that vote failed 45-51, halting the proposed bill in its tracks. Maine Sen. Susan Collins, a senior member of the Appropriations Committee and the Defense Appropriations Subcommittee, was the only Republican senator who voted to advance the bill.

The National Defense Authorization Act — or NDAA — is an annual piece of legislation that directs how federal funds should be used by the Defense Department. It authorizes a certain amount of funding for military hardware, including ships for the Navy, but doesn’t determine what companies should get those contracts.

Maine’s Sen. Angus King, a member of the Senate Armed Services Committee, criticized the senators who voted against advancing the bill for not prioritizing the country’s national security because they feel the bill needs more amendments. He urged them to consider the 202 amendments already in the package, many of which were supported by Republicans.

Before the failed vote, King reminded his colleagues the defense bill “ought to be a boring vote” because it has passed with bipartisan support for 60 consecutive years. King pleaded for them to not add politics to the annual bill because it deals with the defense of the nation, which should remain a bipartisan issue.

“This is the national security of this country, this is a pay raise for our troops, this is national security that our people depend upon – that’s our most fundamental responsibility,” King said on the Senate floor Monday. “The preamble of the Constitution: one of the key responsibilities is to provide for the common defense. That’s why you have governments in the first place. We’ve done it for 60 years in a row, I urge my colleagues, this isn’t a moment for partisanship or for playing about and saying ‘I didn’t get my amendment, so I’m not going to vote for it.’”

Collins agreed with King, adding passing the annual defense bill is “one of Congress’ most important responsibilities.”

“Congress has passed an NDAA every year for the past 60 years, and this year should not be any different given the importance of this bill,” Collins wrote in a statement Tuesday. “I am urging both sides to reach an agreement to pass the NDAA and the Defense Appropriations bill to ensure our country is prepared to respond to proliferating threats around the world.”

As it stands, the Senate’s version of the NDAA would authorize $3.7 billion for two Arleigh Burke-class destroyers, among other military hardware, directly reversing President Biden’s initial call for only one Arleigh Burke in his draft of the military bill.

Collins said she voted to advance the NDAA because it would both “strengthen our national security and support hardworking Mainers at BIW, Portsmouth Naval Shipyard, Pratt & Whitney, and elsewhere across our state who make invaluable contributions to our defense.

Arleigh Burkes, often called the “workhorse of the Navy” by King, are built by only two shipyards in the country: BIW and its competitor, Mississippi-based Huntington Ingalls. When the Navy has entered into multi-year contracts for several Arleigh Burkes in the past, BIW and Huntington Ingalls have shared the work.

The president was expected to ask for two Arleigh Burkes, so his proposal received immediate pushback from lawmakers, including the Maine delegation, and lawmakers got to work proposing amendments that reversed the president’s proposal.

Other than two Arleigh Burkes, the Senate’s version of the NDAA authorizes a nearly 3% pay raise for military servicemembers and Department of Defense civilian workforce and gives 12 weeks of parental leave for military personnel.

The House passed its version of the NDAA in September, which includes amendments for three Arleigh Burke-class destroyers and authorizes the Navy to enter into a multi-year contract for 15 Arleigh Burkes over five years beginning in fiscal year 2023.

When the Senate eventually passes its version of the NDAA, the House and Senate will come together to hash out the differences between their two versions of the defense bill before the final version is brought to the president before the end of the year.

Though King reminded the lawmakers the NDAA has passed for 60 consecutive years, the bill had a turbulent year last year when then-President Donald Trump vetoed the bill because lawmakers didn’t add language that would have removed a legal shield for social media companies.

Congress ultimately voted to override Trump’s veto and the bill was passed without the addition Trump demanded.