There are moments fertile for apocalyptic anxiety — numerologically specific dates, perhaps, or seemingly significant ones like the year 2000 — but nothing sparks the apocalyptic imagination like a time of existential distress. For President Trump, that moment is now. In response to an impending impeachment vote in the House of Representatives, he sent a letter to House Speaker Nancy Pelosi (D-Calif.) on Tuesday that reveals more than now-familiar tantrums and rage. This text is a window into his own eschatology, his theology of the End Times. For Trump, impeachment is not a political problem: It is the climax of a holy war that he must win.

Throughout history, the letter has been one of the literary genres most closely associated with apocalyptic texts. The Book of Revelation is framed as a letter, and the letters of Paul are rife with apocalypticism. One of the most important medieval apocalyptic texts, Adso of Montier-en-Der’s “Letter of Adso to Queen Gerberga on the Origin and Time of the Antichrist,” is a literal letter from the abbot to the queen of Germany. Christopher Columbus reveals his role as a new John of Patmos repeatedly in the five letters that come down to the present day. And during the First Crusade, especially, letters, or chronicles framed as letters, shed light on the most apocalyptic worldviews among the crusading contingents.

And this is, indeed, what Trump’s letter is: a warning framed as a missive, meant not for Pelosi’s eyes alone but as a broader declaration of Trump’s worldview, a chronicle of his reign, a threat of impending peril for the United States and a vision of history centered on Trump himself. It is, in effect, an apocalyptic text, more reminiscent of the eschatological letter-chronicles of the past than any legal document of rebuttal. The only things missing are the horsemen.

The text opens with the president protesting “the partisan impeachment crusade” of the Democrats in the House. The word choice of crusade, of course, no longer reflects the papally issued holy wars of the Middle Ages — indeed, “crusade” is used routinely for any political movement seen as being overly zealous against a particular target. But Trump’s use of “crusade” gives a framework for the central apocalyptic crutch of his entire administration: the notion of an existential, good-vs.-evil, apocalyptic duality surrounding his term of office that includes him as a semi-messianic figure.