Try one of the following sentences. “President Trump has made some excellent appointments, but it is unacceptable to mock the family of a deceased American soldier.” “I’m glad that the president is cutting taxes, even if he never released his own tax returns as promised.” “It’s right to scrap Obamacare, but it’s wrong to threaten tariffs against Mexico.”

The point is not that these statements are right or wrong — plainly people can disagree about that — it’s that you never hear them. American politics is an all-or-nothing affair, in which you root for one team and despise the other.