Ordinarily, Democrats should be sitting pretty. Even in elections when a president of the opposing party is reelected overwhelmingly—a likelihood this November given the roaring Trump economy—the House seldom switches hands. When Richard Nixon won 49 states in his 1972 reelection, Republicans only picked up twelve House seats. When Ronald Reagan was reelected in 1984 with a similar 49-state victory, the pickup for Republicans was sixteen seats. Neither election came close to flipping the House.

What about this November, when Republicans would need a net gain of at least eighteen seats to win the House? Democrats need to worry about the 80th Congress, one of only two led by Republicans in the Democrat-dominated period between President Herbert Hoover’s 1932 defeat and Speaker Newt Gingrich’s 1994 revolution. Democratic President Harry Truman capped Republican congressional rule at two years by running in 1948 against the “do-nothing” Congress.

Truman’s claim was mendacious since the 80th Congress was enormously consequential, passing the Marshall Plan, the National Security Act that created the Department of Defense and CIA, and the Taft-Hartley Act that broke unions’ monopoly on the supply of industrial labor. But today’s House of Representatives really has accomplished nothing, other than acquiescing to Trump’s triumphant replacement of NAFTA.