So we keep hearing that VA and NJ always or often vote against the President's party in the subsequent year. At electoral-vote.com, they have a chart showing this happening 14 of 16 times since 1980. So let's push it further. Here are my thoughts:
1. If VA or NJ voted against the incumbent president's party but consistent with that state's vote in the previous year's presidential election, the election shows continuity, not a shift against the president's party.
2. Does it matter what happened before 1980? I don't see why 1980 is a cutoff for measuring unless we know something happened, or unless we with to hypothesize that some change must have happened in 1980.
Here are my expanded data:
|Year||Prior Pres Elect||VA Vote Pres||VA Gov||NJ Vote Pres||NJ Gov||VA||NJ|
The coding is: 2 means state voted against incumbent president and changed its party preference from the previous election. 1 means the state voted agaisnt the incumbent president but consistent with its prior presidential electoral vote. 0 means it voted for the incumbent president, consistent with its prior presdential electoral vote. -1 means that it voted for the incumbent president and inconsistently with its prior state vote agaisnt that president.
What we see is (1) the pattern is not so strong as remarked and (2) it really only relates to a handful of elections.