For his unexpected surge in the nascent contest for the Democratic presidential nomination, Pete Buttigieg, 37, can thank his formidable intellect, his considerable poise and political instincts that have been close to flawless so far.

But his greatest debt of gratitude goes to Donald Trump.

Ask Buttigieg-besotted voters whether his youth gives them pause and they’ll say that extra seasoning sure didn’t improve the taste of Trump. Question whether serving as mayor of a small Indiana city is adequate preparation for being the leader of the free world and they’ll say that it’s infinitely preferable to a background in reality television, casinos and beauty pageants.

Kamala Harris’s fans like her smarts, toughness and flashes of warmth. But you know what some of them like even more? The idea of Trump’s presidency being bracketed by a black predecessor and a black, female successor. That casts Trump’s values as outliers, untrue to America. It shrinks him to a costly one-off, a wretched asterisk.

Every incumbent president looms large over the contest to determine his opponent, but the shadow cast by Trump is bloated beyond measure. He’s not just influencing the Democratic race. He’s perverting it. It looks and sounds little like 2016, 2012, 2008 or any other year that I can easily recall, and the main reason isn’t rising progressivism, increasing diversity or metastasizing social media. It’s Trump.