The terrible thing about what has happened in the Senate is this: the intellectual and institutional infrastructure of legal and political systems can confer a kind of revenant legitimacy even on claims and verdicts that destroy those systems. You can murder a democracy with democratic institutions. The Nazi Party did not come to power in a coup; it came to power in an election. When the Nazi Party finally did suspend German democracy, it did so using the institutional language of the state that the Nazis were destroying.
So while we can all see the plain insanity of Alan Dershowitz’ proposition that if a President of the United States believes his own election is in the national interest, no action that he takes to secure his own election is therefore impeachable, it still matters that it was said on the floor of the Senate with the blessing of the current Administration and that it will be incorporated into the logic of the foregone acquittal that the Republican Senators will shortly be delivering.
Institutions are a kind of railroad track into the near-term future, laid down in haste as the train approaches. If the track is laid down pointing to a yawning canyon with no bridge over it, the engineers of the train do not have the option to swerve or evade the abyss ahead.
Dershowitz–and thus the GOP–are now fully committed to single-party rule, to an assertion that if they believe themselves the only legitimate rulers of the United States then it is so and they need fear no law nor principle as a barrier to their continued hold on power. As Dershowitz renders it, Trump would be doing nothing against his oath of office if he ordered a Democratic candidate investigated by the Justice Department or detained by the FBI for no other reason than to damage their candidacy. He could legitimately order federal money withheld from the home state of a political rival or for that matter legitimately impede or interfere with elections in jurisdictions likely to vote for any opponent. It’s not hard to think of quite real actions that will shortly be given political blessing (with the likely blessing of the Roberts Court to follow), because many of them are employed in authoritarian states that hold sham elections–tampering with the vote count, intimidation of opposition voters, arrests or detention of opposition candidates, refusal of legal supervision or eyewitnessing of election procedures, and so on. Dershowitz has sanctified all of that.
It doesn’t matter if 99% of the law professors in the nation think him wrong and craven. If his views stand as the prologue to an acquittal, they will be in some sense laying down the tracks that the train cannot help but follow.