A toned-down defense bill is looking likely. That could hurt Johnson.

Negotiations between the House and Senate over defense policy legislation are down to the wire — and the final product will be a major test of Speaker Mike Johnson’s durability with his right flank as a potential clash looms with conservatives.

Johnson, now in his second month on the job, is already taking heat from conservatives over government funding, Ukraine aid and other issues. But the Louisiana Republican will soon have to sell his conference on a compromise National Defense Authorization Act that’s certain to be less conservative than the version the House passed this summer.

When the text of the bill is out, conservatives will judge the legislation by whether the culture war provisions they pushed to include — including limits to the Pentagon’s abortion travel policy, funding for medical treatment for transgender troops and military diversity programs — made it into the final product.

But other issues, including a potential extension of foreign surveillance authorities, must still be sorted out by party leaders in both chambers. That wrangling has delayed the likely filing of the compromise bill until early next week, according to three people familiar with the process. All were granted anonymity because the timing has not yet been announced.

For a Congress that hasn’t been terribly productive, passing the bill offers lawmakers at least one major accomplishment to tout to their constituents. And with a 61-year history of passing the NDAA into law, lawmakers often see it as a reliable vehicle for legislation unrelated to defense.

Many conservatives who have opposed defense bills in previous years supported a nearly party-line version this year loaded with right-wing proposals. A compromise bill that waters down or drops many of those proposals in order to pass the Democratic-led Senate will almost certainly lose their support, and could further sour them on Johnson and other GOP leaders.

Rep. Jim Banks (R-Ind.), an Armed Services member who was named to the conference committee to negotiate the bill, said he's hopeful conservatives will see wins in their fight against diversity efforts and other personnel policies they argue distracts the military from its main missions.

But a compromise NDAA could hurt Johnson within the ranks if Republicans don't come away with wins on that front.

"If the NDA is watered down or weakened and doesn't address some of these core issues to combat wokeism in the military, then that won't be helpful to any of the Republican leaders who are part of it," Banks said. "There will be a lot of Republicans who will not vote for it if it maintains the DEI programs."

It’s unlikely the defense bill will trigger the same kind of clash that brought down Speaker Kevin McCarthy. But recent moves that antagonized conservatives indicate patience on his right flank may be wearing thin, and compromising on the defense bill gives those lawmakers more ammo. Only a handful of dissident Republicans need to break ranks to grind the House to a halt.

A spokesperson for Johnson declined to comment.

When it comes to the defense bill, many Republicans are prepared to accept a more moderate package that passes with the help of Democrats and can win President Joe Biden’s signature.

“In the end, you may lose 30 or 40 [House] Republicans, but you’re going to have a massive bipartisan vote on this when it’s all said and done,” said Rep. Don Bacon (R-Neb.).

Conservative Rep. Chip Roy of Texas, a member of the Rules Committee that determines what bills go to the floor and who has pushed for more conservative Pentagon legislation, accused GOP leaders of trying to include the Section 702 surveillance authority extension to help pass what far-right members consider a lackluster defense bill.

"They want to use that to move a crap NDAA. We all know it. Everybody knows it. Everybody gets the joke," Roy said. "So if the majority leader, if the speaker, if Republicans want to go out and campaign on this crap they get to own it."

Conservative groups could also put pressure on Republicans if they drop the abortion language. A spokesperson for Heritage Action confirmed to POLITICO that the advocacy group told lawmakers on Thursday that it is considering advocating against passage of the bill if the abortion provision is removed.

Nearly all House Democrats opposed the initial GOP bill in July after an amendment was added that would block the Pentagon’s policy to reimburse the costs for troops who must travel to seek abortions. As negotiations progressed, top Democrats warned that insisting on the provision would tank a final bill.

Lawmakers in both parties contend that, as speaker, Johnson is committed to passing a final bill and continuing the over six-decade streak of defense legislation becoming law each year, even if it means going against his desire to block the Pentagon abortion travel policy.

“The speaker has very clearly stated that everyone realizes we won't get everything we want, and that’s one way to say ‘compromise,’” said Senate Armed Services’ ranking member, Roger Wicker (R-Miss.). “So I think the leadership of both parties at both ends of the building realize there’s been a lot of give and take, and there’ll be a lot, and we’re close to wrapping this up.”

Wicker said the provision is a red line for Senate Majority Leader Chuck Schumer and suggested it might come out, with Republicans opting to fight it in other ways.

Defense hawks are also counting on Johnson’s tenure on the House Armed Services Committee, unique among recent speakers, as a sign that he sees bipartisanship as the only path forward.

Rep. Rob Wittman (R-Va.) said Johnson “understands what he has to balance there in terms of the interests of,” House Republicans and, “what he needs to do to get it through” the Democratic-controlled Senate.

“I think he is focused on getting it done in a form that gets as many votes on our side of the aisle as possible,” Wittman said at the POLITICO Defense Summit this month. Rep. Joe Courtney (D-Conn.) also noted at the event that Johnson “has got the muscle memory of voting for bipartisan NDAAs.”

Still, conservatives may not walk away from the negotiations empty-handed.

Both the House and Senate versions of the bill include provisions taking aim at some diversity programs, including a cap on salaries for Pentagon employees involved in diversity, equity and inclusion efforts. Both bills also include GOP-favored language requiring the Pentagon to dispose of unused border wall materials with the aim of allowing states to finish barriers on the U.S.-Mexico border.

It’s unclear whether that will be enough to satisfy conservatives. Asked whether rank-and-file Republicans would fall in line behind a more centrist bill than they passed four months ago, House Armed Services top Democrat Adam Smith said, “We'll see.”

“People bluster and talk and all that, but there's an increasing lack of understanding of how compromise in the democratic process works, and increasingly people are like, 'If I don't get my way, I'm gonna burn the place down,’” said Smith, who has also expressed confidence in Johnson’s ability to compromise. “I will say this: we've had a very fair process. We've got a pretty good balance between Democrats and Republicans.”

Jordain Carney contributed to this report.