Senior reporter

Democrats have been confronted with an uneasy choice regarding former FBI director James B. Comey. He's the guy many of them believe cost them the 2016 presidential election, but they would also very much like to believe the things he's saying about President Trump. That means threading a needle between the horrible things you might have said about his character and actions in 2016 and maintaining that he should be trusted now.

Or, in the case of Rep. Maxine Waters (D-Calif.), snapping the needle in half and declaring that you believe Comey when he says things you like.

Appearing on MSNBC on Monday night, host Chris Hayes played a clip from January 2017 of Waters declaring after a classified hearing that Comey had “no credibility.” Waters, who seemed to know what was coming, laughed awkwardly for a few beats and then explained.

“I’ve tried to clarify that and to say, yes, coming out of that classified briefing, I said that, and I certainly meant it,” she said. “However, I think it is quite different when you take a look at Comey and his relationship to the president, what he said, what he’s done. I believe him.”

She added: “I believe him. And so then was then, and now is now.”

Indeed.

Part of being a politician is showing that you have some consistent moral compass — that you don't just promote things and people because they say things you like and denounce them when it's inconvenient. Saying Comey has “no credibility” means he lacks character and can't be trusted to tell the truth. That doesn't really change with circumstances and with the passage of 15 months.

What's more, Waters said she “certainly meant it” when she said Comey had no credibility. So either she's acknowledging that she is a bad judge of credibility (and probably shouldn't be trusted to judge it today), or she's admitting to a thoroughly convenient political evolution.

Politicians aren't viewed as the most consistent and trustworthy people; in fact, Gallup polling shows that members of Congress are basically tied with lobbyists as the least-trusted of 21 professions tested. And sometimes they show us why.