The problem for Trump is that the few areas of ideological overlap don’t come close to outweighing the long list of issues where Sanders and Trump are practically opposites. Sanders supports a carbon tax; Trump calls global warming a hoax. Sanders wants a $15 minimum wage; Trump has said “our wages are too high.” Sanders wants to jack the top income tax rate up to 54 percent; Trump wants to slash it to 25 percent.

Their foreign policies do not dovetail that neatly. Sanders’ anti-imperialist fans would not echo Trump’s call to “take the oil” in Iraq. Nor would they want to “authorize something beyond waterboarding” for suspected terrorists, let alone “take out their families.”

Then there is the enormous gulf on race. Sanders has linked Trump’s proposed ban on Muslims entering the country to Adolf Hitler’s Holocaust, as a reminder “what a lunatic can do by stirring up racial hatred.” While Sanders rails against excessive police violence and mass incarceration; Trump has said the police are “absolutely mistreated” and endorsed a beating of a Black Lives Matter protester at one of his rallies, saying “maybe he should have been roughed up.”

And when Donald Trump tried to hold a rally in Chicago, it was Bernie Sanders supporters, outraged by Trump’s racially divisive rhetoric, who took over the arena and chased Trump out of town.