In Priebus, Trump first tried the kind of low-key, steady hand that what’s left of the GOP establishment thought he needed as a novice politician. Surely the longest-serving national chairman in the Republican Party’s history, who had held the Republican Party together through fractious years and helped it reclaim the presidency, could be a calming, rational manager in the White House.

But from the beginning, the fit was awkward. During the 2016 campaign, Priebus had repeatedly beseeched Trump to modulate his message and play well with the other candidates in the crowded Republican field. Trump, who has always been his own chief strategist, communications guru and political director – and who was winning by running his way — saw that as a sign of weakness, and responded accordingly.