House Republicans pulled their health-care bill shortly before a vote on Friday, and for once the media dirge is right about a GOP defeat. This is a major blow to the Trump Presidency, the GOP majority in Congress, and especially to the cause of reforming and limiting government.

The damage is all the more acute because it was self-inflicted. President Trump was right to say on Friday that Democrats provided no help, but Democrats were never going to vote to repeal President Obama’s most important legislation. And that’s no...