Politically, Buttigieg and Klobuchar are both hawking middle-of-the-road, tell-it-like-it-is personas, which they argue Democrats need to carry the Midwest, the region they call home. They are both competing to emerge as the main moderate alternative to Bernie Sanders, the current polling frontrunner.

But the rivalry runs deeper than their political positioning. Klobuchar has regularly spoken about sexism on the campaign trail, explaining that she is willing to call out “double standards” for female candidates because “we have to grapple with the fact that some people think a woman can’t win” against Trump, she told POLITICO in January. And this fall, Klobuchar said that a woman with the former mayor of South Bend’s resume and qualifications would likely not be on the presidential debate stage or get treated as a serious national candidate.

Klobuchar’s frustration with Buttigieg bubbles up most intensely when it comes to that experience.