A lobbyist friend who visited Capitol Hill recently came away horrified. “I now am ready to believe that the partisanship is so unhinged that it’s a threat to the Republic,” she writes in an email.

This Washington hysteria comes at a time of full employment, booming stocks, relative peace and technological marvels like an electronic robot named Alexa who fetches and plays for you songs of your choice. What’s the fuss about?

We...