According to a federal district court, the subpoena power of Congress gives it access to President Trump’s personal financial records. While this is an important decision, it’s only a prelude to a decision on appeal. As we’ve seen before, the President sometimes prevails in the end after losing initially. And there are good arguments that the President’s lawyers can make to the U.S. Court of Appeals for the D.C. Circuit, and possibly the U.S. Supreme Court, to try to limit the scope of the subpoena.

As the district court recognized, when Congress pursues its investigations of Presidents, it must do so in a way that serves a “legitimate legislative purpose.” Congress cannot use its investigatory powers simply to expose the private affairs of individuals, nor may it intrude into the powers of the executive or judicial branches.

In light of the requirement of a legitimate legislative purpose, the district court considered the four purposes that U.S. Rep. Elijah Cummings, Chair of the House Oversight Committee, has invoked for the Committee’s investigation of the President. According to Cummings, the Committee seeks to determine (1) “whether the President may have engaged in illegal conduct before and during his tenure in office,” (2) “whether he has undisclosed conflicts of interest that may impair his ability to make impartial policy decisions,” (3) “whether he is complying with the Emoluments Clauses of the Constitution,” and (4) “whether he has accurately reported his finances to the Office of Government Ethics and other federal entities.”

How do these purposes line up with the subpoena? The House Committee requested Trump’s accounting firm to provide copies of a wide range of documents, including audited financial statements and documents relied upon to prepare the financial statements. In addition, the Committee sought the documents not only for Trump as an individual, but also for affiliated entities, such as the Trump Organization and the Trump Foundation. The records were to cover the period from 2011 to 2019.

On appeal, the following questions will be important. To the extent that the Committee is investigating Trump’s conduct since taking office, such as whether he has undisclosed conflicts of interest, why is the Committee requesting records that go back to 2011? Shouldn’t the request begin with his presidency or perhaps his presidential campaign?

With respect to whether Trump engaged in illegal conduct before taking office, that would explain the need for the earlier records, but the D.C. Circuit and/or Supreme Court will ask whether Congress actually has a legitimate “legislative” purpose at stake. As indicated, Congress may not use its investigatory powers to intrude on the powers of the other branches, and responsibility for policing lawbreakers is lodged with the executive and judicial branches. While Congress writes laws, the other branches enforce them. On the other hand, as the district court observed, illegal conduct of the President would be relevant to the congressional power of impeachment.

And here is where things become unclear. Presidents may be impeached for illegal conduct while in office, and they may be impeached for illegal conduct designed to corrupt the electoral process, as with President Nixon and Watergate. But it’s not clear that Presidents can be impeached for illegal conduct that took place while they were still private citizens and not campaigning or serving. Indeed, the House Judiciary Committee declined to bring impeachment charges against President Nixon on account of his tax evasion. (The evasion actually occurred while Nixon was President, but may have been perceived as insufficiently related to his official duties).

On this score, the district court cited the Senate’s Whitewater investigation of President Clinton. That did involve conduct before Clinton’s election as President, but Clinton was serving in office as the Arkansas Attorney General at the time of the alleged misconduct. The House Oversight Committee’s concerns about Trump’s financial conduct were prompted by Michael Cohen’s testimony that Trump exaggerated or discounted the value of his assets as it suited his purposes when seeking bank loans or paying taxes as a private citizen.

Still, the House Committee has an important response–in a 1993 case involving the impeachment of a federal judge, the Supreme Court held that questions about the impeachment process were matters for Congress rather than the courts to resolve. So it would seem to follow that it would be for the House to decide whether it could file impeachment charges on the basis of financial misconduct by Trump before he became president and therefore whether it had a legitimate purpose in investigating his financial activities. But there’s an important caveat. The Supreme Court may have felt constrained in the 1993 case because it would have reviewed the impeachment of a judicial colleague, and that would have entailed a conflict of interest for the Justices. With a Trump impeachment, no such conflict would exist for the Court.

There are a couple of other arguments for the House Committee that are less weighty. As the district court observed, investigating a President’s misconduct can lead to legislative proposals, as in the case of the reforms that followed Watergate. But if the Committee envisions reforms for private financial activities, it would be seeking records from many people in addition to Trump. The Committee also has expressed concerns about the “hush money” payments to Stormy Daniels and Karen McDougal during the 2016 campaign, but that wouldn’t justify records back to 2011, nor would it justify a sweeping range of records.

In balancing the different considerations, the district court cited its responsibility to give Congress broad authority to exercise the legislative powers, including the power of investigation. So a key factor will be whether the D.C. Circuit and/or Supreme Court approach the case with the same degree of deference. All in all, there is sufficient uncertainty on the law such that we could see the subpoena upheld or be restricted in its scope.