It was mid-June, and relations between Donald J. Trump and the news media had taken another dreadful turn. He had already vowed to change the libel laws to make it easier to sue journalists, and his personal insults were becoming more vicious. (One news correspondent was a “sleaze”; another was “third rate.”)

Most troubling was that he was keeping a blacklist of news organizations he was banning from his rallies, and it was growing.

I called him at the time, to see what this would look like in a Trump administration. Would he deny White House credentials to select reporters and news organizations?

No, he said. “There, I’m taking something away, where I’m representing the nation.”

We can only hope he means it. Because if Mr. Trump keeps up the posture he displayed during the campaign — all-out war footing — the future will hold some very grim days, not just for news reporters but also for the American constitutional system that relies on a free and strong press.