Don’t be deluded by Mr. Biden’s sales pitch about a single-issue “exception” to the 60-vote filibuster rule. This is like an engineer saying he wants to relieve pressure on the Hoover Dam by blasting a small section of concrete. The result wouldn’t be a trickle. Mr. Biden previously called for “making the exception of voting rights for the filibuster.” Is a carve-out for climate bills next?

Once the legislative filibuster is killed for one priority, it will go for everything. That’s what happened to the filibuster on judicial nominees. In 2013 Democratic Senate leader Harry Reid used the “nuclear option” to confirm some appellate judges. Sen. Mitch McConnell’s prescient reply: “You’ll regret this, and you may regret this a lot sooner than you think.” In 2017 Mr. McConnell returned the favor by nuking the filibuster for Supreme Court nominees. Three conservative Justices later, Roe v. Wade went on the ash heap.