There's revolution in the air. Donald Trump and Bernie Sanders might occupy opposite political extremes, but the extravagantly coiffed billionaire and the rumpled anti-billionaire are both surfing a tsunami of voter disgust. Their fans have much in common: a deep distrust of the political establishment, the conviction that wealth in America no longer trickles down, and a susceptibility to magical thinking. Trump promises to rid America of millions of illegal immigrants, destroy ISIS, bring back millions of jobs from China, and restore the lost status of the white working class. Sanders vows to transform America into a socialist paradise like Scandinavia, where everyone will get free health care and college educations and gladly pay trillions more in taxes. Ask either candidate how he'll get his radical proposals through Congress, and overcome the opposition of at least 60 percent of the country, and you get the same true-believer response. This is a revolution! Details to come later.

You can't blame the Trumpists and Sanderistas for their wishful thinking. Washington is broken. The economy no longer works for tens of millions of people. The other presidential candidates are deeply flawed and uninspiring. Yet history, and reason, would suggest some skepticism about Trump's and Sanders' pledges. Outside their fan bases, their ideas have virtually no support, and attempts to impose them would spark vehement counter-revolutions. If Trump really did try to round up and deport 12 million people, at least half the states would actively resist, and there'd be something akin to a civil war. If Sanders tried to jack up taxes and take over the entire health-care system, he'd meet the same overwhelming resistance in Congress that he did in 25 years as a legislator, when three of the 353 bills he introduced passed — two of them renaming postal offices in Vermont. Talk of revolution is easy and exciting. Change is hard.