The evidence is in, and the conclusion is solid: Trump supporters are gullible.

Trump made a lot of campaign promises. Most amounted to inane sloganeering, but to his loyalists, that was enough.

One of his most effective lies promises was that he would appoint a special prosecutor to go after Hillary Clinton, and to “lock her up,” as he alluded to during one of their debates.

The Trumpidians ate it up, and the chants of “Lock her up!” became a constant at his remaining rallies.

Apparently, some of his loyalists missed the interview where he talked about the Clintons being “good people” and how he said he didn’t want to hurt Hillary by pursuing an investigation, as he’d previously promised to his followers.

Trump was speaking in Grand Rapids, Mich., as part of his “thank you” tour when he heard some chants of “lock her up” — a common refrain during his campaign events. “That plays great before the election — now we don’t care, right?” Trump responded, according to CNN.

Except that’s not what his supporters signed on for. They bought the whole notion of a rigged election, “crooked Hillary,” and a President Trump who would bring justice where the FBI and Republicans with the House Select Committee had failed.

After FBI Director James Comey in July recommended not charging Clinton, Trump cited it as evidence the election was “rigged” and said the FBI “rolled over.”

So was the election rigged, or not?

The original premise was that he would lose because the fix was in, but now that he’s won, nothing matters, including his grand campaign promises.

His devotees are going to have to learn to live with that.