Which of our two great political parties is the stronger? Maybe it makes more sense to ask which of the two is weaker.

The case that the Republicans are weaker is easy to state. Democrats have won four of the last six presidential elections, from 1992 to 2012, and won a plurality of the popular vote in a fifth. This is a vivid contrast from the period 1968 to 1988, when Republicans won five of six presidential elections.