The only other three generals-—other than Washington-—to be president were not Republicans: Jackson, Harrison, Taylor. Washington was a Federalist.
A good thing to keep in historical perspective is that the Democrat party today is in reality the Communist Party with retention in name only.
See post 157, there were a lot more than 4 Generals who became President. The most recent notably was Ike, who was a Republican. Quite frankly, Jackson, although a Dem, was probably the most conservative President (in the current definition) this country ever had. He was the only one to ever completely pay off the national debt, he gave the banks hell and cut their power over government, he also did not put up with crap from the terrorists of his day (Indians).
Franklin Pierce was another Democratic President who was once a general. He was a brigadier general in the Mexican-American War.