Not all of these candidates will be with us after the CNN Detroit debate. Here’s why

(CNN)California Rep. Eric Swalwell was about to walk on to the biggest stage of his political career: the first Democratic presidential debate. “It’s a balance between horning your way in and sharing who you are and what you believe, but not being obnoxious,” Swalwell told CNN’s Gloria Borger in an interview. The stakes at CNN’s Democratic debate in Detroit are high. New criteria will make it considerably harder to qualify for the next debate in September. And for much of the field of more than 20 candidates, the more difficult threshold will be impossible to clear, barring a game-changing moment. “Maybe 12, 13 of these candidates, there’s not going to be another shot after this. To some extent, not qualifying …