President Trump formally threatened to veto a $740 billion military spending bill Tuesday hours before the House passed the legislation by a veto-proof majority, heralding a potential showdown between the White House and Congress over a bipartisan effort to rename several Army posts that commemorate Confederate generals.

The president’s threat — and House lawmakers’ response — is a moment of reckoning for Senate Republican leaders, who must decide whether to allow votes on key bipartisan modifications to their version of the annual defense bill that might incur a similar veto warning, or attempt to tailor their legislation to stay closer in line with Trump’s wishes.

In a statement, the White House listed several provisions of the House’s legislation that the president considers objectionable, chief among them a directive to the Pentagon to rename the 10 bases within a year. While avoiding mention of the Confederacy, White House advisers nevertheless called the order “part of a sustained effort to erase from the history of the Nation those who do not meet an ever-shifting standard of conduct” and an attempt “to rewrite history and to displace the enduring legacy of the American Revolution with an ever-shifting standard of conduct.”

Trump’s move, which had been expected, failed to prevent the Democratic-controlled House from approving its version of the defense bill four hours later, in a vote of 295 to 125. Among House Republicans, 108 voted for the bill.

But while the veto threat was focused solely on the House bill, it also presents a challenge for the Republican-controlled Senate, where lawmakers are debating a parallel measure ordering similar changes to bases named for Confederate officials, albeit under a three-year timeline.

Trump’s veto threat makes no mention of the speed with which lawmakers want the names changed; it objects to there being any mandate at all.

Senators are expected to vote on their bill next week. In the meantime, they are waiting on leaders in that chamber — particularly Senate Armed Services Committee Chairman James M. Inhofe (R-Okla.) — to indicate whether there will be votes on proposed amendments that could either bring the Senate more in line with Trump’s wishes or put that chamber on a similar collision course with the White House.

Inhofe has indicated a preference not to change the bases’ names, but he has not announced whether an amendment from Sen. Josh Hawley (R-Mo.) that would remove the mandate, replacing it with a study process, will get a vote in the Senate. Legislation also is pending from Senate Democrats that would accelerate the three-year timeline to one year.

Trump’s veto threat is not based on the issue of Confederate names alone. The president’s advisers also objected to other provisions in the House bill that would restrict the commander in chief’s ability to redirect troops and other service members at will — including language to block Trump from removing U.S. troops stationed in Germany until the administration can show that maintaining such a presence in Europe is no longer necessary. A bipartisan group of senators wants to take a similar step.

Last month, the president approved a plan to remove 9,500 of the approximately 35,000 U.S. troops stationed in Germany, in a move that was roundly criticized by both Democrats and Republicans. In the House, lawmakers responded this month by including a provision in their defense bill requiring the administration to first prove to Congress that redirecting those forces would not negatively affect the United States or its allies.

In the Senate, Mitt Romney (R-Utah) has been pushing for a similar provision in its version of the defense bill. His bipartisan amendment is co-sponsored by Republican Sens. Lindsey O. Graham (S.C.) and Marco Rubio (Fla.), suggesting that if the legislation came up for a vote, it could secure enough votes to pass. Inhofe, who has expressed his disappointment with the decision to withdraw troops from Germany, has not said whether Romney’s amendment will be considered on the Senate floor.

Representatives for Inhofe did not respond to requests for comment Tuesday.

Before any bill is sent to the president’s desk, the Senate and the House must work their separate versions into one product that can pass both chambers. At this stage of the process, it is not unique for the president to issue a veto threat. President Barack Obama regularly threatened to veto the defense bills that emanated from the Republican-controlled chambers of Congress, and in 2015 made good on his threat by vetoing a bill in a dispute over federal spending.

But the top-line matters over which Trump has threatened to veto this year’s defense spending measure — or at least the House’s version — reflect issues over which Trump has faced disapproval from lawmakers, including members of his own party. Democrats and a large swath of the Republican Party have criticized Trump for playing fast and loose with traditional European allies since he took office, and many such as Romney say that shifting troops away from Germany would be a “free gift to Russia.”

Likewise, removing the names of Confederate generals from military installations is an initiative whose critics appear to be concentrated in the president’s political base, though a broader swath of GOP lawmakers have objected to the idea of making such changes by congressional mandate. Many of the president’s supporters have also voiced objections to the nationwide protests against racially motivated police brutality.

The House’s bill would require all federal law enforcement officers who are dispatched to help quiet protests to clearly display the insignia of the force they belong to, and require the top official of a state, territory or the District of Columbia to consent before the National Guard is deployed there to conduct certain support operations. The White House objected to the latter provision in its veto threat as well, arguing that it would give too much power to the D.C. mayor “to deny the president” use of the National Guard “to defend the seat of the United States Government.”

Earlier this month, the Pentagon banned displays of Confederate flags at military installations. The House’s defense bill seeks to expand that ban in statute to cover all Confederate symbols displayed on military facilities, except in museums and similar settings.