This post has been updated.

President Trump on Friday issued his first veto at president. In doing so, he nullified Congress’s vote to disapprove of and halt the national emergency declaration he is using to build his long-promised border wall.

The veto would seem to render pointless the bipartisan votes of disapproval — especially since neither the Democratic-led House nor the GOP-led Senate had anything close to the two-thirds majorities they would need to override the veto. But even if the veto is upheld, that to doesn’t mean the votes won’t ultimately matter.

As I argued Thursday, the disapproval in and of itself was significant for its size and effect. We have seen over and over again how a closely divided GOP-controlled Senate has come close to rebuking the president. Almost always, the holdouts have been prevailed upon to toe the line in the end. When enough Republicans have crossed over to rebuke Trump, it has almost always been in symbolic ways: Jamal Khashoggi, Trump’s trade wars, the media not being “the enemy of the people,” and the withdrawals from Syria and Afghanistan.

This time, there was meat on the bone. The GOP-controlled Senate actually took concrete action to stop Trump, thereby forcing Trump to veto something. This registers that he is acting in clear opposition to — and overturning — the will of Congress.

That matters from a PR standpoint. Congress not only declined to give Trump the money for his border wall even when he shut down the government over it, but now it explicitly disapproved of his effort to get around its decision not to appropriate the money. That’s two rebukes on the same issue, and Trump is pushing past both of them.

The question from there is whether those twin rebukes might also matter for the legal battle. However people feel about this particular national emergency declaration, Congress did give the presidency rather broad authority to declare such emergencies. When it passed the National Emergencies Act in the 1970s, it handed over some of its constitutional authority over the purse strings of government. That authority has not been tested like it is now, but that does not mean the courts will necessarily say it goes too far.

One of the opponents of the national emergency declaration, Sen. Rand Paul (R-Ky.), thinks that it will. He actually predicted that the Supreme Court will strike down the national emergency declaration if and when it comes to that point, and he said Congress’s votes would matter.

“We spent the last two months debating how much money should be spent on a wall, and Congress came to a clear conclusion: $1.3 billion,” Paul said in announcing his opposition. “Without question, the president’s order for more wall money contradicts the will of Congress and will, in all likelihood, be struck down by the Supreme Court.”

Ohio State University law professor Peter M. Shane also said the votes could matter:

The joint resolution underscores the big-picture constitutional dimension of the fight. Congress’ power of the purse is its heavy artillery in the scheme of checks and balances. The Constitution underscores its significance through redundancy. Not only does Article I vest the spending power in the legislative branch, but a separate provision bars the executive branch from spending money unless appropriated. If presidents can find ways to work around Congress’ rejection of their requested spending priorities, Congress’ big gun has been silenced.
A joint resolution underscoring that Congress has deliberately rejected the inclusion of border wall fencing in response to a presidential request could well move a court to say that this statute will not help finance it.

Jessica Levinson of Loyola Law School told me this is likely to come down to whether the courts (a) decide to narrowly interpret the statute or (b) focus more on whether there is actually an emergency and whether Trump has this authority.

“It certainly adds weight to the idea that this is executive overreach and a blatant and problematic end-run around Congress,” Levinson said. “They not only decided not to appropriate the funds, but are saying even more definitively, ‘Do not do this. Do not go around us.’”

Levinson pointed to the Supreme Court’s decision to uphold Trump’s travel ban last year, though, as an example of how it might keep its focus on the statute. The court said in its 5-4 decision that determining Trump’s underlying motives — including about potentially banning Muslim immigration — from his tweets and public comments was beyond its responsibilities. Since then, Trump has appointed and gotten another justice confirmed, Brett M. Kavanaugh.

In this case, though, the court would not have to surmise how Congress feels about its authority being usurped; it would have votes on which to base the idea that Congress clearly did not want Trump to take an action involving a power that it afforded him.

The courts could also reason, of course, that if Congress really dislikes what Trump is doing, it could stop him by providing more votes.

“It is also possible that some justices who are more inclined to support the administration would take the view that Congress has it within its power to terminate the national emergency and has failed to do so, and so the court should not step in and do something that Congress wasn’t willing or able to do itself,” said Keith E. Whittington of Princeton University. “But the fact that Congress would have only failed because of the high bar of a veto override should weaken that latter position somewhat.”

In short, we have no idea how compelling the courts will find these votes, but it’s possible they may not just be another toothless symbolic rebuke.