After Donald Trump was convicted last week in his hush-money trial, Republican leaders wasted no time in rallying behind him. There was no chance the Republican Party was going to replace Trump as their nominee at this point. Trump has essentially taken over the G.O.P.; his daughter-in-law is even co-chair of the Republican National Committee.

How did the Republican Party get so weak that it could fall victim to a hostile takeover?

Daniel Schlozman and Sam Rosenfeld are the authors of “The Hollow Parties: The Many Pasts and Disordered Present of American Party Politics,” which traces how both major political parties have been “hollowed out” over the decades, transforming once-powerful gatekeeping institutions into mere vessels for the ideologies of specific candidates. And they argue that this change has been perilous for our democracy.

In this conversation, we discuss how the power of the parties has been gradually chipped away; why the Republican Party became less ideological and more geared around conflict; the merits of a stronger party system; and more.

Mentioned:

“Democrats Have a Better Option Than Biden” by The Ezra Klein Show

“Here’s How an Open Democratic Convention Would Work” by The Ezra Klein Show with Elaine Kamarck

Book Recommendations:

The Two Faces of American Freedom by Aziz Rana

Rainbow’s End by Steven P. Erie

An American Melodrama by Lewis Chester, Godfrey Hodgson, Bruce Page

Thoughts? Guest suggestions? Email us at ezrakleinshow@nytimes.com.

You can find transcripts (posted midday) and more episodes of “The Ezra Klein Show” at nytimes.com/ezra-klein-podcast. Book recommendations from all our guests are listed at https://www.nytimes.com/article/ezra-klein-show-book-recs.

This episode of “The Ezra Klein Show’‘ was produced by Elias Isquith. Fact-checking by Michelle Harris, with Mary Marge Locker, Kate Sinclair and Rollin Hu. Our senior engineer is Jeff Geld, with additional mixing by Aman Sahota and Efim Shapiro. Our senior editor is Claire Gordon. The show’s production team also includes Annie Galvin and Kristin Lin. Original music by Isaac Jones. Audience strategy by Kristina Samulewski and Shannon Busta. The executive producer of New York Times Opinion Audio is Annie-Rose Strasser. Special thanks to Sonia Herrero.

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