The House Armed Services Committee will debate dozens of amendments to the fiscal 2019 defense authorization bill during its marathon markup on Wednesday, when lawmakers could introduce a wide variety of proposals, such as authorizing the Pentagon to develop new nuclear weapons and allowing transgender troops to serve in the military.

The legislation, commonly referred to as the National Defense Authorization Act, or NDAA, typically draws broad bipartisan support. But the markup is likely to include debate on some of the most controversial defense issues, including transgender troops, low-yield nuclear weapons and downsizing the Pentagon’s civilian workforce.

President Donald Trump’s proposed border wall and military parade could also surface.

Social issues

Debate on transgender rights for military servicemembers could emerge as one of the most fractious NDAA issues, as it did last year.

The Pentagon last month announced that transgender people “who require or have undergone gender transition are disqualified from military service.” The Defense Department, though, will allow troops currently in the military to stay as long as they serve according to their birth sex.

This directive follows multiple court rulings against Trump’s initial ban on transgender military service and has earned the support of Republican Rep. Vicky Hartzler of Missouri, who last year offered a failed amendment that would have banned the use of defense funds for gender reassignment procedures.

With the new Pentagon directive in place, Hartzler’s office says she has no plans to reintroduce an amendment similar to her previous proposal. Democrats, however, may float amendments to reverse the new Pentagon rule.

Watch: Trump and House Leadership at Odds on Legislative Agenda Heading Into May

Trump priorities

The NDAA will be among the few major bills Congress considers ahead of midterm elections in November, making debate on nondefense issues that get wrapped into the defense policy bill that much more likely.

Members of the Armed Services Committee whose states border Mexico could use the bill as a vehicle to keep Trump from erecting a wall along the U.S.-Mexico border. Last year, Republican Steve Knight of California and Democrats Beto O’Rourke of Texas and Ruben Gallego of Arizona successfully offered amendments that banned funding for a border wall.

Trump’s desire for a wall has not diminished, though, and he has since ordered National Guard troops to the border to assist Customs and Border Protection in their duties.

Members of the committee may also use the markup to try to ensure that Trump’s proposed military parade through the streets of Washington remains limited in scope and funding. Trump has pushed for the parade since seeing a French military parade last summer that featured military vehicles and planes driving through and flying over Paris.

Members of both parties and some retired military leaders oppose the parade on the grounds that it would waste money. Others worry that such a show of military force in the streets of a U.S. city is not in the American tradition and would be inappropriate.

The Pentagon has already released plans for the parade, which would coincide with a long-running Veterans Day parade in Washington. The current plans include a “heavy air component” at the end of the parade — jets flying overhead — but prohibits tanks from participating as the metal tracks could damage city streets.

Nuclear weapons and space

Expensive and powerful weapons programs are also likely to be debated during the markup.

While all of the six Armed Services subcommittees have filed their portions of the bill, some punted complicated issues to the full panel. For example, the Strategic Forces Subcommittee, responsible for nuclear weapons, did not address low-yield nuclear weapons in its portion of the bill, despite calls from the Pentagon’s Nuclear Posture Review in February for the development of a new sea-launched cruise missile and ballistic missiles tipped with low-yield warheads.

The Strategic Forces Subcommittee is also in charge of the military’s space operations, and its mark this year would call for a unified Space Command within U.S. Strategic Command.

That proposal to overhaul the Pentagon’s space operations is the latest from the subcommittee’s chairman, Mike D. Rogers of Alabama, and ranking member Jim Cooper of Tennessee. Last year the duo tried to create a separate military service dedicated to space, called the Space Corps, which would have been housed within the Air Force.

The Space Corps proposal ultimately failed, and the bill instead mandated a study on the efficacy of such a force. That study is expected to be completed in August.

The fact that the study is three months from being published could dampen support for another Space Corps push. The markup, though, is one of the few legislative opportunities to create such a force, and Rogers has repeatedly signaled his intent to establish the service branch. Trump recently suggested that he might be open to the idea of a “space force.”

A spokesman for Cooper said he would “like a Space Corps to be created sooner rather than later.”

Bureaucratic overhaul

Legislative debates over pricey weapons programs and social issues have typically been among the most contentious in the committee markup. But a bureaucratic overhaul plan from full committee Chairman Mac Thornberry of Texas could induce rare partisan debate between the chairman and the ranking member, Adam Smith of Washington.

Thornberry last month introduced a bill he plans to fold into the NDAA that would cut 25 percent from the budget of Pentagon support agencies, sometimes referred to as the fourth estate, which handle such tasks as logistics, contracting and real estate, with an annual budget of over $100 billion.

Smith believes the proposal is hasty and could have unintended consequences.

“It appears this proposal could do serious damage to DOD’s information infrastructure, testing ranges, and community support, as well as the basic DOD functions in the National Capital Region by eliminating critical agencies in one stroke,” Smith said in a statement. “Those are important functions that I don’t think we should discard if we haven’t done careful study and analysis.”

Thornberry also introduced a bill aimed at speeding up Pentagon weapons-buying, which already has Smith’s support. He plans to roll the proposal into the authorization measure.

While the legislation is sure to include dozens of provisions that would advance Trump’s goal of strengthening the military, the markup offers lawmakers a chance to include proposals unpopular with the White House that nevertheless will not attract a presidential veto. This is because the bill, which has been signed into law for 56 years straight, often earns wide bipartisan support and includes provisions such as military pay raises and weapons purchases that Trump is eager to approve.