The Republican extremists killed the idea, leaving the scheme without enough votes. They are no longer interested in symbolic blows against the health law; there have already been scores of those votes. They actually think they can get the Senate, and ultimately the president, to approve the defunding of the health law — Mr. Obama’s most important achievement — by threatening to harm the nation and the economy.

This is pure delusion. Democrats are never going to undo the law, especially knowing the size of the self-inflicted wound Republicans would suffer if they really did force a shutdown or, far worse, a default. But the powerful forces on the right don’t care about reality. The Club for Growth, a conservative group, announced it would use its dreaded ratings system against any Republican who supported a continuing resolution that did not “defund Obamacare.”