Sen. Joe Donnelly, D-Ind., deserves, of all Democrats, to be most pitied.

It isn’t just that Donnelly voted against Supreme Court Justice Brett Kavanaugh. It is that the Indiana Democrat keeps changing his story. Take his answer from last night’s debate with Republican challenger Mike Braun. Donnelly told the audience he “voted against Judge Kavanaugh because of concerns about his impartiality and concerns about his judicial temperament.”

That would be a perfectly good answer, if only it were completely true.

Donnelly made a big show of opposing the Kavanaugh nomination after allegations of sexual assault surfaced but before senators delayed the vote to allow for an FBI investigation. At that time, Donnelly said he couldn’t vote for the nominee because Majority Leader Mitch McConnell, R-Ky., had “refused to allow that FBI investigation.” At that point, Donnelly said nothing about Kavanaugh's impartiality or judicial temperament.

Then Sen. Jeff Flake, R-Ariz., demanded the FBI get involved. He handed Donnelly exactly what Donnelly said he wanted, and so the Democrat had to come up with a new excuse and he had to come clean in the process. See this exchange between Donnelly’s office and Seung Min Kim of the Washington Post:

This is particularly damning for Donnelly and his brand of Midwest centrism. The senator has held on in deep-red Indiana — a state Trump won by double digits by the way — because of his ability to tack toward the middle. If the FBI never investigated Kavanaugh, Donnelly wouldn’t be in this predicament. Better yet, if Donnelly had a consistent rational for evaluating nominees, the electorate could feel confident their senator wasn’t playing politics.

This will dog Donnelly until Election Day as Republicans point to fact checks, like those published by the AP, slamming the senator for making “misleading claims.”