STEVE INSKEEP, HOST:

There was a moment when it seemed that Liz Cheney's brand, her family name, might sustain her. She is, of course, the daughter of former Vice President Dick Cheney. He was a graduate of the University of Wyoming more than half a century ago. And he was, himself, elected to Congress in Wyoming as long ago as 1978. Allan Lichtman is professor of history at American University. Good morning.

ALLAN LICHTMAN: Good morning.

INSKEEP: Isn't there a tradition of politics as a family business?

LICHTMAN: You know, that genteel tradition has been shattered in America by two enormous historical forces. One is political polarization, which has made ideology or adherence to the party line - in this case, the Trump party line - vastly more important than name recognition, political connections and organization. Based on all of those factors, Liz Cheney, a household word, should have won overwhelmingly in Wyoming. She got slaughtered. The other thing that has undermined political dynasties, of course, is the rise of social media, which is an alternative way to raise funds and to organize. So it's not just Liz Cheney who kind of marked the end of a dynasty. It's also George P. Bush in Florida, who got slaughtered in a primary election against a very vulnerable attorney general.

INSKEEP: I think you're telling me that in a past era, if someone like Liz Cheney had broken with the president of her party, she might have been able to rely on that family name, might have been able to rely on that brand to make connections of her own with voters.

LICHTMAN: That's absolutely right - at one time, but no longer. Brands mean very little. Name recognition means less and less. And family connections have now become, essentially, irrelevant. The Clinton dynasty, the Cheney dynasty, the Bush dynasty - all gone, swept away by history.