Democrats are calculating a left turn. The math is inescapable.

Recent primary results could steer presidential hopefuls in the wrong direction for 2028. The far left is having a moment, and Democratic presidential aspirants are no doubt watching. Progressive activists think they have the key to winning all over the map, buoyed by Abdul El-Sayed’s narrow victory in Michigan’s Senate primary, Wisconsin gubernatorial candidate and state Rep. Francesca Hong’s polling advantage ahead of the Aug. 11 primary and scattered wins by Democratic Socialists of America-aligned candidates. But presidential hopefuls be forewarned: Three warning lights are blinking red. First, even in what looks like a strong Democratic year, these candidates are...