Unredacted documents reported on Thursday by Just Security help show both why the Senate should hold a full presidential impeachment trial and why President Trump’s actions regarding Ukraine were so improper.

The documents show the repeated warnings from Defense Department officials to White House personnel that Trump’s delay in releasing legally mandated aid to Ukraine was unlawful.

Before examining that evidence, though, please consider that this is only one of three ways in which Trump’s actions were so inappropriate as to be impeachable. First, Trump’s request for Ukraine to investigate the Bidens was, on its own, wildly out of bounds. As former ambassador Bill Taylor testified, the president has no authority to ask a foreign government to investigate a U.S. citizen based on that nation’s laws rather than our own.

Second, to turn the request into what amounts (in the vernacular) to an extortionary demand, the now-famous issue of a quid pro quo, is to misuse presidential power while unlawfully seeking a “thing of value” from a foreign entity for use in an American campaign. And, yes, as even some of Trump’s most learned and eloquent defenders admit, the existence of a quid pro quo was obvious.

Third, as I have argued for months, it was illegal for Trump to withhold the military aid even if he had not asked the Ukrainians for anything of personal and political value in return. By delaying the assistance beyond the point at which it could actually be obligated before the budget year ran out, Trump violated the Impoundment Control Act of 1974 and, probably, the Constitution. That 1974 law provides that once an appropriation has been duly passed and signed into law, the president cannot withhold it for policy reasons without formally notifying Congress. Even then, the money must be spent unless Congress approves the president’s request.

While the Impoundment Control Act makes these requirements explicit on statutory grounds, Supreme Court precedent implies (but does not explicitly say) that presidential impoundment of duly appropriated funds is also unconstitutional. In Train v. City of New York, decided in early 1974 but based on facts and laws predating the 1974 impoundment act, the court determined that a president is required to enact the full scope of programs legally mandated by Congress and signed into law. Granted, the court relied even then on statutory language rather than citing a specific constitutional violation made by then-president Richard Nixon. Yet by denying the president the authority to stray from statutory language, the court, in essence, ruled that statutory spending language enjoys constitutional weight.

The newly unredacted documents show that Pentagon officials repeatedly warned the White House that its funding delays were unlawful. By Aug. 26, acting Pentagon comptroller Elaine McCusker was telling the White House that “impoundment paperwork” was “now necessary” because the delays ordered by Trump made it impossible to “obligate” the funding “consistent with the Impoundment and Control Act.”

As it was, more than $35 million of the assistance never did go out the door by the legally required Sept. 30 deadline. That alone was a violation of the law by Trump.

Again and again over the past few months, Trump’s defenders have said, in essence, that the president is a free agent in determining American foreign and defense policy. That assertion is flat-out false. While presidential power is certainly at its most robust on such matters, the president still remains beneath, not above, the law. In this case, he violated the law. The violation should not go unpunished.