The two Trump tax return cases were argued before the Supreme Court yesterday. The first involved three subpoenas from House of Representative committees. The second a subpoena from New York County District Attorney, Cyrus Vance Jr. While both involve tax returns and Trump, they are very different cases with very different issues.

That said, both have an overlapping problem. What limits, if any, should there be on such actions that involve, indirectly, the person who holds the presidency? At the moment, that person is Trump, who raises a great many problems because of who he is, what he’s done, and how much he’s despised. But whatever rule is handed down, it will apply not just to Trump, but to every president who follows.

If a congressional committee controlled by the party opposing the president decides to go after the president, whether to dig up dirt to use against the president or just to embarass or harass the president, they could subpoena anything from medical records to credit card bills. Maybe there will be something that can weaponized against the president. Maybe it will just be an annoyance. But if Congress has the unfettered power to subpoena anything they want as long as it has a “plausible legislative purpose,” it can use that power to go after every opposing party president in the future. Remember, it might be Trump today, but he won’t be president forever.

As to the district’s attorney authority to subpoena, the problem is somewhat different. While the authority to investigate and issue grand jury subpoenas is well established, objecting to the subpoena would be little different for the president than anyone else. Much as the argument was rejected in the Paula Jones case, the burden of dealing with it wouldn’t be so much of a burden on the job of president as to make him unable to perform the duties of office.

But there are about 2300 local prosecutors in the United States. What if it wasn’t one subpoena, but 2300? Or, a bit more modestly, one percent, 23 subpoenas? There are procedural stumbling blocks, such as jurisdiction, but presidents get around, so it’s not entirely outside the realm of possibility.

The Vance case lent itself to possible limit, a heightened scrutiny of such subpoenas as to their justification and necessity, when directed at the personal effects of the president. But the lawyer arguing for the House in Trump v. Mazars, Douglas Letter, failed spectacularly when pushed.

In today’s oral argument in Trump v. Mazars, the attorney for the House of Representatives was asked (repeatedly) to identify a limit on Congress’ subpoena power, and he came up empty. He was unable to identify any information about the President that Congress could not demand.

The problem is that Congress can theoretically legislate about anything, and can, if one shuts one’s eyes tight enough, come up with a “plausible” connection between its subpoena and a subject of legislation. If they want President Warren’s medical records, they can claim it’s related to legislating about health care. If they want President Sanders’ credit card bills, they can claim it’s related to legislating about banking legislation. It may be nonsensical, but then, so was the rationale for subpoenaing Trump’s tax returns. Bear in mind, it’s not what you wish the reason was, but what the House said the reason was.

Cornell prawf Mike Dorf was similarly critical of Doug Letter’s whiff at offering a single example of any limit on Congress. Josh Blachman, on the other hand, suspects Letter didn’t blow the question at all, but rather intentionally refused to offer any limit to place the Court in the more difficult position of having to give Congress all or none.

Was Letter “unable” to answer the questions in Mazars? Or was he “unwilling” to provide a limiting principle? I lean towards the latter. It is very likely that his client, the House, refused to concede any additional limits on its own powers. If the Court wanted to impose such limits, so be it; but the House would not acquiesce.

Here, the House may have not wanted to risk further cabining their subpoena authority for future cases that do not involve the President. After all, the House conceded that Article II and executive privilege provides some limits. But the questions from the Justices went further. Moreover, when pressed on a limiting principle, Letter had answers at the ready. The answers were largely non-responsive, but he didn’t stumble like he did at other times. I think Letter’s responses were deliberate.

What makes this case controversial is that feelings toward Trump, who claimed he would disclose his tax returns when his audit was over but never did, and still hasn’t, are so extreme. What they will reveal remains a mystery. While they won’t have a line that says “Payments from Putin for doing his bidding,” it may well show things that are deeply embarrassing, potentially unlawful or hypocritical. If they were good for Trump, he would have disclosed them. That he hasn’t is about as clear a measure that he’s got something to hide.

But will Doug Letters’ failure, or refusal, compel the Supreme Court to rule that there are no limits on what a congressional committee can subpoena from a president? Even if they are claimed to be sought and held in confidence, they will be revealed with impunity. Under the circumstances, there is good reason to suspect that Josh has a point, that the House will never have as strong an argument with public support for unfettered authority given that Trump is the target. Why concede any limit on Congress’ power when they can put the Trump screws to the Court, making the Court come off as the bad guy who would deny the public’s representatives the ability to do their job? Few will give much thought to how this will impact President Ta-Nehisi Coates.

On the other side, the Vance subpoena has a far better chance of prevailing, but because it’s a grand jury subpoena, and given New York’s strict grand jury secrecy laws, it’s unlikely to see the front page of the New York Times. A win by Vance will be unsatisfying, as it will put Trump’s tax returns in Vance’s grasp but still not be available for public inspection and consideration. And even if Vance gets them, there remains a question of what he can legally do with them anyway.