Few things in life are more predictable than the chances of an incumbent member of the U.S. House of Representatives winning reelection. With wide name recognition, and usually an insurmountable advantage in campaign cash, House incumbents typically have little trouble holding onto their seats—as this chart shows.

U.S. House Reelection Rates, 1964-2018

Senate races still overwhelmingly favor the incumbent, but not by as reliable a margin as House races. Big swings in the national mood can sometimes topple long time office-holders, as happened with the Reagan revolution in 1980. Even so, years like that are an exception.