Barack Obama will retire a happy man. He is now close to destroying his political enemies---the Republican Party, the American conservative movement and the public-policy legacy of Ronald Reagan.

Today, the last men standing amidst the debris of the Republican presidential competition are Donald Trump, a political independent who is using the Republican Party like an Uber car; Ted Cruz, who used the Republican Party as a footstool; and John Kasich, a remnant of the Reagan revolution, who is being told by Republicans to quit.

History may quibble, but this death-spiral began with Barack Obama's health-care summit at Blair House on Feb. 25, 2010... That meeting was the last good-faith event in the Obama presidency. Barack Obama killed politics in Washington that day, because he had no use for it, and has said so many times. The Democrats survived the Obama desert by going to ground. But frustrated Republicans outside Congress eventually started tearing each other apart.