Sen. Max Baucus (J. Scott Applewhite/AP) Sen. Max Baucus (J. Scott Applewhite/AP)

The Post’s Paul Kane broke the news that Sen. Max Baucus (D-Mont.) will retire rather than seek reelection to the seat he has held since 1978. This is huge, folks. The third-most senior member of the Senate, Baucus is the chairman of the powerful Senate Finance Committee. Most important for today’s discussion is that Baucus also voted against a bill that would require background checks for gun purchasers. And it was that vote against the will of 90 percent of the American people that Howard Dean, the former Vermont governor and former chairman of the Democratic National Committee, predicted last week would be the end of the road for Baucus.

“I will predict this is the end of his career,” Dean said on Morning Joe last Thursday. “Yeah, either Baucus will retire or lose the primary to [Schweitzer].” Schweitzer is Brian Schweitzer, the former governor of Montana who Dean said had a 20-point edge over Baucus in a recent poll. The survey Dean was referring to was from Public Policy Polling which declared, “The biggest threat to Baucus might actually be in a primary. Former Governor Brian Schweitzer would lead him 54/35 in a face off.”

The national anger unleashed by the Senate’s inaction on background checks was immediate. The rage against Democrats who voted no was just as immediate. Bill Daley, the former White House chief of staff, publicly demanded his money back from Sen. Heidi Heitkamp for her no vote and asked his fellow Democrats to withhold campaign donations from her and others.

Even though Baucus won reelection in 2008 with 73 percent of the vote, he was seen as a ripe target. Liberals in Montana viewed him with suspicion. Republicans in that state like Republicans everywhere detested his role as an architect of Obamacare. The vote against background checks very well could have been the last straw for Montana Democrats.

Dean boldly predicted last week, “Bring Schweitzer into the race and he’ll be the next Democratic Senator from Montana.” Democrats better hope Dean is right — again.

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