Complex sentence: Reagan's win was the first time a Republican had won an absolute majority of the popular vote in Massachusetts since 1956, although it was still Reagan's narrowest win in the nation, thus making it the second most Democratic state after Minnesota.
Split into simpler sentences: Reagan's win was the first time a Republican had won an absolute majority of the popular vote in Massachusetts since 1956. It was Reagan's narrowest win in the nation, making it the second most Democratic state after Minnesota.