Mueller couldn’t say, with any “confidence,” that the president of the United States is not a criminal. He said, stunningly, that “if we had confidence after a thorough investigation of the facts that the President clearly did not commit obstruction of justice, we would so state.” Mueller did not so state.

That’s especially damning because the ultimate issue shouldn’t be — and isn’t — whether the president committed a criminal act. As I wrote not long ago, Americans should expect far more than merely that their president not be provably a criminal. In fact, the Constitution demands it.

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The Constitution provides for impeachment and removal from office for “Treason, Bribery, or other high Crimes and Misdemeanors.” But the history and context of the phrase “high Crimes and Misdemeanors” makes clear that not every statutory crime is impeachable, and not every impeachable offense need be criminal. As Charles L. Black Jr. put it in a seminal pamphlet on impeachment in 1974, “assaults on the integrity of the processes of government” count as impeachable, even if they are not criminal.

And presidential attempts to abuse power by putting personal interests above the nation’s can surely be impeachable. The president may have the raw constitutional power to, say, squelch an investigation or to pardon a close associate. But if he does so not to serve the public interest, but to serve his own, he surely could be removed from office, even if he has not committed a criminal act.

By these standards, the facts in Mueller’s report condemn Trump even more than the report’s refusal to clear him of a crime. Charged with faithfully executing the laws, the president is, in effect, the nation’s highest law enforcement officer. Yet Mueller’s investigation “found multiple acts by the President that were capable of executing undue influence over law enforcement investigations.”

Trump tried to “limit the scope of the investigation.” He tried to discourage witnesses from cooperating with the government through “suggestions of possible future pardons.” He engaged in “direct and indirect contacts with witnesses with the potential to influence their testimony.” A fair reading of the special counsel’s narrative is that “the likely effect” of these acts was “to intimidate witnesses or to alter their testimony,” with the result that “the justice system’s integrity [was] threatened.” Page after page, act after act, Mueller’s report describes a relentless torrent of such obstructive activity by Trump.

Contrast poor Richard M. Nixon. He was almost certainly to be impeached, and removed from office, after the infamous “smoking gun” tape came out. On that tape, the president is heard directing his chief of staff to get the CIA director, Richard Helms, to tell the FBI “don’t go any further into this case” — Watergate — for national security reasons. That order never went anywhere, because Helms ignored it.

Other than that, Nixon was mostly passive — at least compared to Trump. For the most part, the Watergate tapes showed that Nixon had “acquiesced in the cover-up” after the fact. Nixon had no advance knowledge of the break-in. His aides were the driving force behind the obstruction.

Trump, on the other hand, was a one-man show. His aides tried to stop him, according to Mueller: “The President’s efforts to influence the investigation were mostly unsuccessful, but that is largely because the persons who surrounded the President declined to carry out orders or accede to his requests.”

As for Trump’s supposed defense that there was no underlying “collusion” crime, well, as the special counsel points out, it’s not a defense, even in a criminal prosecution. But it’s actually unhelpful in the comparison to Watergate. The underlying crime in Watergate was a clumsy, third-rate burglary in an election campaign that turned out to be a landslide.

The investigation that Trump tried to interfere with here, to protect his own personal interests, was in significant part an investigation of how a hostile foreign power interfered with our democracy. If that’s not putting personal interests above a presidential duty to the nation, nothing is.

The report shows contacts beyond those previously known.

For example, Petr Aven, the Russian head of Alfa-Bank, Russia’s largest commercial bank, told investigators that Mr. Putin regularly meets with about 50 Russian oligarchs at the Kremlin. In a late 2016 meeting, he said, Mr. Putin instructed him to reach out to the Trump administration about United States sanctions against Russia.

Through an intermediary, Mr. Aven reached out to a Russian-born foreign policy specialist in Washington, Dimitri Simes, who had previously met with Jared Kushner, the president’s son-in-law, hoping to arrange a meeting to discuss “a high-level communications channel between Putin and the incoming administration,” the report states. The effort was called “Project A.”

In a Dec. 22, 2016, email, the intermediary wrote Mr. Aven that “with so much intense interest in the Congress and the media over the question of cyber-hacking (and who ordered what), Project A was too explosive to discuss” at that time.

The report also leaves questions about the interactions of some Trump aides with Russians, partly because some witnesses were uncooperative.

Investigators learned, for example, that Mr. Manafort shared internal campaign polling data with Mr. Kilimnik, who prosecutors have repeatedly said is linked to Russian intelligence agencies. At Mr. Manafort’s instruction, Rick Gates, the deputy campaign chairman, repeatedly transferred data to Mr. Kilimnik, using an encrypted form of communication, beginning in spring 2016 and continuing even after Mr. Manafort was fired from the campaign in August.

The report said that Mr. Gates understood Mr. Kilimnik would give the polling data to pro-Russian Ukrainian oligarchs who had previously hired Mr. Manafort, as well as to Oleg V. Deripaska, a Russian billionaire considered so close to the Kremlin that he is sometimes referred to as “Putin’s oligarch.” Mr. Deripaska has denied he ever received the polling data.

At the Aug. 2, 2016, meeting with Mr. Kilimnik, Mr. Manafort outlined “the status of the Trump campaign and Manafort’s strategy for winning Democratic votes in Midwestern states,” the report stated. While investigators found no evidence that the polling data helped Russian operatives shape their election interference operations, the report said they could not “reliably determine Manafort’s purpose” in sharing the data. Nor could they figure out what, if anything, Mr. Kilimnik ultimately did with it.

They also questioned Mr. Manafort’s denial that he never discussed Mr. Kilimnik’s plan to effectively cede part of eastern Ukraine to Russia with Trump campaign or administration officials, saying he had lied to them about the subject previously.

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Mr. Gates, the former campaign deputy, told prosecutors that by late summer 2016, the Trump campaign had incorporated the possible release of hacked emails into its political strategy. En route to La Guardia Airport that summer, the report stated, “Candidate Trump told Gates that more releases of damaging information would be forthcoming.”

Although that paragraph is partly redacted, other accounts suggest that Mr. Trump had learned that from Roger J. Stone Jr., a former campaign adviser who was in contact with the Russian hackers. Mr. Stone is now awaiting trial on charges of lying about his efforts to reach Julian Assange, the founder of WikiLeaks, and trying to influence the congressional testimony of a witness with ties to Mr. Assange.