For obvious reasons, I’ve lately been pondering examples from recent history where political nominees have proved too toxic for their own parties. There are more than a few examples—Tom Hayden, David Duke etc.—but only one with anything like contemporary resonance: The 1966 gubernatorial election in Maryland.

The Democratic primary that year was divided four ways, which enabled the least likely contender—a Baltimore paving contractor and perennial candidate named George P. Mahoney—to win the nomination with just 30 percent of the vote. Mahoney was a familiar, and unwelcome, figure to a majority of Maryland voters. And in the midst of the Great Society, his campaign’s principal theme, which was opposition to open housing legislation, provided a catchy slogan (“Your Home is Your Castle”) which delighted his longtime, indeed fervent, supporters, but embarrassed most Democrats. Among those Democrats were my very left-wing parents, whose memories of Mahoney-as-spoiler were long and distinctly unfavorable.