President Trump, writer. Photo: Alex Wong/Getty Images

If you worked in print media, you became accustomed to receiving long, unhinged letters from agitated members of the general public. Often these letters tied together facts, pseudo-facts, paranoid insinuations, dramatic though false legal interpretations, unconventional punctuation, and occasionally, threats. It is at this point unsurprising, though still quite unsettling, to read one of these letters from the hand of the president of the United States.

Trump’s letter to House Speaker Nancy Pelosi is obviously written, or at least dictated, in large part or in whole by the president himself. Its most notable quality is its lack of any coherent structure. It does not build an argument, or even group like points together. It careens wildly from point to point.

Trump’s letter strengthens the case for impeachment in two important ways. First, he portrays impeachment as constitutionally illegitimate. By this, Trump doesn’t mean simply that his actions do not rise to an impeachable offense, or even that the accusations are completely meritless. He repeatedly denies that the House has any constitutional right to undertake impeachment at all.

“This impeachment represents an unprecedented and unconstitutional abuse of power by Democrat Lawmakers, unequaled in nearly two and a half centuries of American legislative history,” he insists. “By proceeding with your invalid impeachment, you are violating your oaths of office, you are breaking your allegiance to the Constitution, and you are declaring open war on American Democracy … it is no more legitimate than the Executive Branch charging members of Congress with crimes for the lawful exercise of legislative power.”

Of course the Constitution gives the House of Representatives the power to determine what presidential acts constitute impeachable offenses. Trump seems to believe that he as president has the power to determine whether a president’s actions are impeachable. Trump argues that if Congress can impeach him, which is a clearly delineated power, then he can prosecute Congress for crimes of Trump’s choosing, a power that exists nowhere in the Constitution.

The most telling passage comes at the end, where, having unloaded various grievances, Trump lingers on the psychic pain that the Russia investigation and now impeachment have inflicted:

After three years of unfair and unwarranted investigations, 45 million dollars spent, 18 angry Democrat prosecutors, the entire force of the FBI, headed by leadership now proven to be totally incompetent and corrupt, you have found Few people in high position could have endured or passed this test. You do not know, nor do you care, the great damage and hurt you have inflicted upon wonderful and loving members of my family. You conducted a fake investigation upon the democratically elected President of the United States, and you are doing it yet again. You are the ones interfering in America’s elections. You are the ones subverting America’s Democracy. You are the ones Obstructing Justice. You are the ones bringing pain and suffering to our Republic for your own selfish personal, political, and partisan gain.

Trump identifies first his family, and then the Republic, as the parties enduring this mental anguish, no doubt in an effort to feign stoicism. But the letter makes it perfectly clear that Trump himself is in agony, to the extent where his mental health is very much in question.

If a juror in Trump’s coming impeachment trial had no other evidence except this letter, it would provide ample grounds for impeachment. Trump openly denies the Congress’s constitutional prerogative, and makes plain his mental unfitness for the job.