Unless a seriously credible opponent begins working now to plan a challenge to President Trump for the Republican presidential nomination, he will win the nomination by default and then drag his whole party down to electoral depths not seen since the post-Watergate lows.
Worse even than 1974, however, the devastation to supposed Republican principles could be unprecedented. At least post-Watergate there remained plenty of conservative Southern Democrats, and the Democratic Party nationally was moving back somewhat to the center after being shocked into reality by the 49-state loss by leftist George McGovern. Today, on the other hand, the Democratic presidential field is a battle between far Left, farther Left, and crazy Left. And there is no longer a tradition of cross-partisan comity on Capitol Hill or even of semi-shared values to moderate legislative action or executive fiat.