Democrats were alarmed last spring and summer when polling suggested that voters ages 18 to 29 were softening in their longtime commitment to the Democratic Party. After the November election, when exit polls indicated that Kamala Harris had won the young adult vote by only a slim margin (if that), it seemed that the ground had shifted. A post-inauguration cover story in New York magazine on young Trump supporters partying it up in Washington captured a widespread impression that this was a generational realignment: the rise of a cadre of MAGA youth.

After examining new survey data and interviewing more than 100 young adults for a book I’m writing on how politics is reshaping the college experience, I’m doubtful. Young MAGA types may feel newly energized and empowered, but empowerment is different from numerical growth. The data suggest that the swing in young adults voting for Donald Trump did not reflect a major shift in ideology. Rather, the swing seems to have resulted from moderate-to-somewhat-liberal young voters deciding to bet on Mr. Trump out of concern about the state of the economy — and from young moderates and progressives who chose to stay home because they thought Ms. Harris was either too progressive or not progressive enough. This is a point with implications for Democrats and Republicans alike.