The last time that Joe Manchin was facing real pressure, not the sound and fury of progressives tweeting angrily and futilely at him, the one remaining national Democratic officeholder from West Virginia was blunt: “Washington Democrats are making it more difficult for me to be a West Virginia Democrat.” And that was over three years ago. Since then, West Virginia’s senior senator has gone from one of the only Democrats who would work with President Donald Trump to one of the only Democrats who will stymie President Joe Biden’s eagerness to placate congressional liberals by rubber-stamping their expensive agenda. Of course, Manchin has voted with Biden 100% of the time thus far. But that’s because of his disproportionate influence on what comes up for a vote at all. Joe Manchin isn’t the most powerful man in...