Let’s do a thought experiment. Imagine a candidate far outside the US political mainstream becomes the presidential nominee for one of the two major parties. Besides a seeming hostility to the Washington establishment, that candidate exhibits opposition to the national security state and major tenets of US foreign policy.

Soon, wave after wave of defamatory news stories breaks, only intensifying after the candidate’s November election victory. Attacks from within the sprawling permanent national security bureaucracy are laundered through the media, which obediently reports any and every claim from anonymous sources, and which employs retired national security officials as talking heads, free in this new political climate to air any outrageous allegations seemingly consequence-free. The claims take on a momentum of their own; the president’s political opponents are soon citing them to call for impeach­ment, even imprisonment, on the grounds of treason and other crimes.

You don’t have to try hard to imagine this. We’ve been watching some version of it unfold ever since Donald Trump became the Republican nominee in 2016. And we may well see a more intense version repeat if Bernie Sanders wins the presidency in 2020.