Barack Obama tricked Donald Trump into self-imploding just before the midterms.

It took Barack Obama one joke to get the president of the United States to sabotage his party’s midterm election chances. Last Saturday in Cleveland, Obama walked rally-goers through the absurdity of Trump’s gold-leafed Oval Office, the paved-over Rose Garden, the helipad, and the billion-dollar ballroom-bunker complex rising where the East Wing used to be. He summed it up in a sentence: Trump…