The name of the bill understates its significance. The National Defense Authorization Act, generally known as the NDAA, might sound bureaucratic, but as regular readers know, it’s actually a massive, annual defense spending bill that funds the United States military.

But that’s not all it does. The NDAA also guides Pentagon policy, touching on everything from troop levels to weapons systems to military personnel policy. It takes months to negotiate the details, and by some measures, as much legislative work goes into this one package as any other bill in a typical Congress.

Traditionally, the NDAA has advanced as bipartisan legislation, and this year it was shaping up to be a rare example of Democrats and Republicans working together on an important bill. The Senate Armed Services Committee, for example, advanced its legislation with a bipartisan 25-1 vote. The House Armed Services Committee advanced its version of the NDAA on a bipartisan, 58-1 vote.

With this in mind, there was reason for optimism that when it came to military spending and policy, Congress would avoid the kind of political food fights that too often tarnish congressional policymaking. That optimism, of course, was misplaced: House Republicans decided to give the NDAA a far-right touch-up on the floor, turning an overwhelmingly bipartisan bill into an ugly vehicle for a culture war. NBC News reported:

The House narrowly passed an annual defense policy bill on Friday after Republicans added provisions on abortion and transgender surgeries — measures that were a nonstarter for Democrats. The legislation, which will have to be reconciled with the Senate’s version, passed in a 219-210 vote.

The final vote wasn’t entirely partisan — four Democrats voted for the bill, while four Republicans voted against it — but overwhelmingly, members voted along party lines.

And how is it that a bill that sailed through committee on a bipartisan, 58-1 vote ended up being so contentious? Far-right House Republicans told their party’s leaders that they’d reject the legislation without votes on a series of culture war amendments. That left GOP leaders with a choice: They could pass the bill with Democratic votes, or they could move the bill sharply to the right, push Democrats away, and pass a partisan version of the NDAA with overwhelming Republican backing.

Not surprisingly, the party chose the latter option, which meant a flurry of votes on amendments last night and this morning that turned a bipartisan bill into a divisive one.

The result is an NDAA that would, among other things, limit abortion access for servicemembers, end diversity training in the military, curtail transgender care, prohibit work on combatting climate change, and even restrict what Defense Department schools can teach.

There is no chance, of course, that the Democratic-led Senate will go along with such measures, and it’s a safe bet that the negotiations to reconcile the House and Senate versions will be incredibly difficult.

Eventually, some kind of compromise is likely to emerge, but the far-right members responsible for making the House version of the NDAA worse have already said they’re not going to support a bipartisan solution. From the NBC News report:

House Freedom Caucus Chairman Scott Perry, R-Pa., said Friday that his members won’t give into a bipartisan compromise. “We are not going to back down. We’re not going to give up on the cause that is righteous and we’re going to keep fighting for it,” Perry said at a press conference with members of the conservative caucus.

Buckle up.