The extremely online partisans of Twitter are convinced that Elon Musk is putting a big thumb on the U.S. electoral scale. On one side, Democrats, Never Trump Republicans, and various other fretters about the health of democracy are pleading with their followers to stick around the platform that the Tesla CEO just bought, at least through the midterms. The thesis seems to be that if they don’t man the social media ramparts, they’ll “cede” an important organizing tool to the right, mis- and disinformation will flood the website unchecked, and the Democrats’ messaging reach will shrink. Advertisement Musk 1000% timed...