Even in a future without such a president, however, speakers can count on unrest, because members know they have little to lose in opposing their leaders.

The disciplinarian days of Sam Rayburn and Tip O’Neill are over. When Congress banned earmarks in 2011, it denied its leaders the ability to punish wayward members by stripping funding for local projects in appropriations measures. Boehner tried to punish his detractors by removing them from committees or grounding them from travel, but he succeeded only in making them martyrs.

Polarization, aided by gerrymandering, also makes the speaker’s job harder. As I noted recently, according to The Cook Political Report, of the 435 districts in the House, only 21 are true “toss-ups,” whereas 344 are considered safe seats. (The rest lean in one direction or the other.) This situation rewards lawmakers who cater to activists who glue themselves to their favorite agreeable cable-news shows, actually watch C-SPAN 3, or follow on the internet the latest controversy over a “motion to recommit.” What used to be inconsequential is now incendiary, igniting the party bases on even the most arcane matters. They pressure their elected representatives to take up arms—and they do, because, as I said, they have little to lose.

Finally, there’s social media, which distorts political realities.