WHEN Mark Twain snarled that politicians were “dust-licking pimps,” millions of furious Gilded Age citizens agreed. Millions more would today. There is a bipartisan consensus that our leaders are fools, a collective feeling in a long tradition of grumbling about American politicians. The problem, as Twain’s generation discovered, is that blaming all politicians makes it harder to throw out the real bums.

There were no opinion polls in the 1870s, but Americans poured out vitriol at politicians as a class. Cartoonists depicted them as vultures and rats; comedians wrote snarky satires of machine politicos, much like we do with “Veep” and other shows today. The phrase “scum of the earth” came up a lot.

And while the Gilded Age didn’t invent corruption, late-19th-century America saw a new willingness to take on political elites. During America’s early years many people were willing to defer to elected leaders. When they grumbled (or rioted), it was more often against political parties as a whole than the class of men who ran them.

Something changed after the Civil War: By the 1870s one Philadelphia writer wondered if any leader was not “the unmitigated scoundrel he is usually taken to be.” With the heroism of the Civil War era fading, ugly battles over Reconstruction raging and millions of easily “misplaced” dollars sloshing around booming cities, there seemed to be no more statesmen left in Washington. The Gilded Age, one historian wrote, “produced only ordinary mortals.”

As they do today, politicians turned on their own parties. Big-government “Radical Republicans” fought the party’s free-trade wing; ex-Confederate “Ku Kluxers” rivaled the pro-immigrant Tammany Hall Democrats. To do so, though, they made politics personal. There was (and is) a real debate to be had about the size of America’s government, but instead of engaging in those questions, many preferred to demonize each other...