By ending their filibuster on the debt limit vote, McConnell prevented Democrats from ending the filibuster for any reason other than naked politics, which is exactly what they don’t want to happen. Their cover was gone and they’d been boxed in.

When you can’t get your way, it’s best to create a scenario where your opponents have to pay the highest price possible for getting theirs. It’s the only thing that’ll give them pause, and your only remaining shot an ultimate victory.

What will Democrats do now? We don’t know. But we do know they would’ve gutted the filibuster under the guise of “saving the country from default.” With it gone, it would’ve been game on for whatever else they wanted to pass. But that dam wasn’t broken, it’s still there now. Which makes it harder and costlier politically if they do it in the future for issues that aren’t “emergency” matters.