There should be lines that this or any president cannot cross without incurring criticism from his own side. That’s because the boundary between neutrality and tacit consent—between their failure to condemn and the suggestion that they condone—may be faint, but it exists. Enabling, like pornography, is difficult to define, but sensible observers generally know it when they see it. Among of its markers is the refusal to use one’s influence to improve a situation one purports, at least privately, to deplore.

That influence is considerable. The president can write off Never Trumpers. But he needs the Reluctant Trumpers in Congress to pass legislation and provide a veneer of respectability, or at least tolerability. They are equally crucial in expanding his electoral base, which the president must do to secure the popular majority he craves. The Never Trumpers may therefore be both uniquely positioned to influence his conduct and uniquely responsible for doing so.