… There’s often talk of a midterm penalty in House races, which is the notion that the party in the White House suffers in midterm elections. That rule did not apply so severely in Senate races prior to 1980: the White House’s party gained seats in the 1962 and 1970 midterms, for instance.
As polarization in Congress has reached record levels over the last 30 years, though, midterm elections have increasingly reflected the midterm penalty rule. Since 1980, the opposition party has found a silver lining in being stuck outside the White House: during midterms, only once have they lost more congressional seats than they won. [cont.]
Harry Enten, The Guardian