On Tuesday afternoon, just hours after Vice President Harris announced that Tim Walz, governor of Minnesota, would be her running mate, Astead sat down with Senator Bernie Sanders in Burlington, Vt.

Mr. Sanders, the Vermont progressive who has twice run for president himself, supported the choice of Mr. Walz.

But a Harris-Walz ticket was not what he was envisioning for 2024. He was a staunch defender of President Biden remaining in the race, arguing that Mr. Biden was best positioned to defeat former president Donald Trump.

Now, since Mr. Biden bowed out and Ms. Harris has stepped in, Mr. Sanders has raised questions about what the Harris campaign’s economic message will be and how she will position herself.

More recently though, Mr. Sanders has been on the campaign trail for Ms. Harris.

His journey is indicative of a larger question facing the progressive wing of the Democratic Party — a question we explore today.

With this new Democratic ticket, are progressives all in for Harris?

On today’s episode: Senator Bernie Sanders, independent of Vermont