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Tonight, 12 Democratic candidates will be debating near Columbus, Ohio. Here’s what I’ll be looking for from the seven candidates with the best chances of winning the nomination:

Elizabeth Warren. Swing voters exist, and they are likely to decide the 2020 election, much as they played a decisive role in 2016 and 2018. So far, Warren has not worried much about appealing to them. Now that she’s the front-runner, can she begin to signal to Democrats that she wants to be ruthless about beating President Trump?

Joe Biden. He has yet to seem sharp for an entire debate. Can he break that streak and alleviate concerns about his ability to withstand a long, vicious campaign? I’m more interested in that than the narrow questions of how he responds to Trump’s false smears against his family.

Cory Booker, Pete Buttigieg and Amy Klobuchar. They are the best-positioned candidates to benefit from Biden’s uneven campaign and win over more moderate Democrats. Can any of the three make an explicit case: I’m stronger than Biden and more electable than Warren?