The filibuster is a modern innovation. It’s not in the Constitution, and it wasn’t used routinely until the 20th century. It’s just a Senate Rule, which can be eliminated by a simple majority.
Senators like the filibuster because it magnifies the importance of each Senator’s vote. It makes each Senator more important, and more powerful. It prevents the Senate from getting much done, but Senators care about their individual power more than they care about serving in a functional institution.
President Trump has called for the elimination of the filibuster, and he’s as right as rain. If you’re running for the Senate, and you support the President’s agenda, it behooves you to campaign on ending it. If you’re a McConnell man, on the other hand, you want to be part of the Senate clique which runs it, and you like the filibuster.
Supporting McConnell, and joining his team, means you get a shot at being in the inner circle. More importantly, it brings cash. McConnell is able to spend millions for his preferred candidate, as he just did in Alabama.
But it beats me why anyone would run in a contested Republican Senate primary as a McConnell man. People want the swamp drained, and Mitch McConnell isn’t just a man of the swamp. He’s the Swamp King. And his money is dirty. It’s swamp money.