Did Kennedy's 1960 wins in New Mexico and Nevada foreshadow their future as Democratic states? Or was it a random aberration that had nothing to do with their future voting behavior?
I'm not sure. However, New Mexico and Nevada were bellwether states throughout most of the 20th century. New Mexico has voted for the winner of the popular vote in every election since it was first admitted as a state (1912), except for 1976, when it, like every other Western state except for Hawaii, voted for Gerald Ford. Nevada, on its part, has voted for the winner of the Electoral College in every election since 1912 except for 1976 and 2016. In 1960, both states maintained their bellwether streaks by backing Kennedy. Kennedy won New Mexico due to his Catholicism, and Nevada because of its ancestral Democratic traditions, dating back to the days of Bryan. Nevada was Democratic-leaning in every election from 1896-1960 except for Eisenhower's landslide wins in 1952 and 1956. It didn't become a Republican-leaning state until 1964, and remained as such until 2008, becoming slightly R-leaning again in 2016.