A man sleeps next to the U.S. border wall topped with razor wire in Tijuana, Mexico, on Sunday, June 9, 2019. (Eduardo Verdugo/AP)

President Trump’s border wall — and the military construction projects he siphoned money from to help fund it — are going to take center stage at the House Armed Services Committee on Wednesday, as it attempts to finalize its annual defense bill amid several deeply partisan policy divides.

The panel’s ranking Republican, Rep. Mac Thornberry of Texas, is planning to challenge provisions in Chairman Adam Smith’s bill that would ban using Defense Department funds to pay for the construction of a border barrier and deny the Trump administration both reprogramming authority and money to backfill accounts the president has tapped to divert money toward border construction. It is part of a broader amendment Thornberry is planning to tack an additional $17 billion onto Smith’s $733 billion defense authorization bill, which would bring it closer to both Trump’s budget request and legislation the GOP-led Senate Armed Services Committee approved last month.

While the Republican effort is unlikely to prevail, it may serve as a preview of fights between the Senate and House, as lawmakers across a divided Congress try to strike a compromise to keep the Pentagon up and running.

Smith (D-Wash.) is adamant that the $733 billion figure — already a larger authorization than last year’s $717 billion defense bill — is “more than adequate” for the military to meet its spending needs, despite Republican arguments that anything less than $750 billion could compromise readiness and troop welfare.

“They have been building their budget based on that $733 billion number,” Smith said Monday at the Center for Strategic and International Studies, adding that while the Pentagon might find ways of spending an extra $17 billion, “whether or not they spend it well is highly debatable.”

But Thornberry says budget caps have forced the Pentagon to make “unwise choices” and that the larger authorization is necessary “to restore installations damaged by extreme weather, military requirements identified by the Services, funding to maintain our nuclear deterrence and ensure its safety, and missile defense.”

The border wall accounts for about $3.6 billion of the additional spending Thornberry is expected to seek Wednesday.An additional $2.3 billion would go toward authorizing Tyndall and Offutt Air Force bases, Cherry Point Marine Corps Air Station and the Marine Corps base Camp Lejeune, which were damaged by hurricanes and flooding, to receive disaster funds appropriated under a military construction bill that has yet to pass the full House.

Yet Republicans and Democrats are expected to be bitterly divided over approving spending for other areas, such as nuclear weapons modernization, investments in conventional weapons vs. next-generation defenses, and the detention facility at Guantanamo Bay, Cuba.

Republicans have accused Democrats of pursuing a “slow-bleed strategy” when it comes to Guantanamo and of refusing to commit the resources the Trump administration has requested to buttress their case that the detention facility is insufficient and should eventually be shuttered. While the bill does not mandate the facility’s closure, it does cap the population at its current level of about 40 inmates and lifts restrictions on transferring those detainees to the United States for medical care. Smith has said that ultimately, it is better “to build facilities in the U.S. and transfer them here” than to maintain a dwindling detainee population at the facility.

Guantanamo does not feature in Thornberry’s $17 billion amendment, though both parties expect Republicans to challenge the matter independently Wednesday. The same goes for a looming dispute over low-yield nuclear weapons — investments to which Smith is philosophically as well as financially opposed, warning that any normalization of nuclear warfare is dangerous. Thornberry’s amendment also seeks to increase spending for certain other nuclear modernization programs.

Smith acknowledged Monday that he does not know whether his own opposition to a dramatic expansion of nuclear investment will prevail in the markup, as other positions endorsed by the panel’s top Democrat are expected to.

“We’re planning on spending too much money on nuclear deterrence,” he said at CSIS. “Now, I can count, and I don’t think I have the votes to change that policy. But what I’ve tried to do this year is to force that debate.”

The debate is sure to continue between the Senate and House, which are poised to pass defense bills differing on these and other issues. They will also have to be reconciled with appropriations bills moving through both chambers of Congress, which are still subject to budget restrictions that Congress has yet to strike a deal to fully alleviate.

But in at least one area that threatened to be contentious during that debate, Democrats and Republicans have reached an apparent consensus, agreeing to create a separate armed force for space within the confines of the Air Force. While the details will have to be fine-tuned between the House and Senate — and while the space-focused force differs from what Trump envisioned — leaders of both parties expressed confidence in the structure that bipartisan negotiators worked out.