In my last post, I said that "Before the 1960s, the political atmosphere at most [universities] was moderate to conservative." There were only a few surveys of students or faculty before the 1960s, and as far as I know none of them asked general questions about political views. However, "straw votes" have regularly been held at Harvard University since the 19th century, and information about the results can be found in the Harvard Crimson archives. Participation seems to have been high, and people appear to have taken them pretty seriously--there weren't many votes for "joke" candidates, and support for major-party candidates didn't swing wildly depending on whether they had Harvard affiliations.
Between 1884 and 1948, the Republicans won the Harvard poll every time except 1912, when Theodore Roosevelt ran as an independent and split the Republican vote. In the 1950s, things got closer: Adlai Stevenson (D) won a narrow victory in 1952 (although the Harvard Republican club charged that there was voter fraud), then Eisenhower (R) came back to win narrowly in 1956, and then Kennedy (D) won in 1960. Kennedy's victory was solid but not overwhelming--Nixon got over 40% of the vote. In 1964, the Republican vote fell to 14%, and in 1968 it fell further, to 11% (less than the combined vote for various minor left-wing candidates). Since then, the Democrats have won the Harvard poll every time except 1980 (when the Independent John Anderson won).
Some other notes:
1. Other colleges conducted similar votes, at least in some elections. One of the most elaborate ones was the "National Collegiate Poll" in 1936, which seems to have included about 50 colleges and universities. Franklin Roosevelt won, but his 53% was well below his share in the real vote (61%). Roosevelt did well in the South and most urban universities, but New England went heavily for the Republican.
2. Yale and Princeton were more strongly Republican than Harvard. In 1960, more than 70% of the Princeton students chose Nixon over Kennedy.
3. Faculty were also allowed to participate in the straw vote, and their votes were sometimes reported separately. The faculty leaned Republican, but were less consistent than the students. For example, the faculty went for FDR in 1936 and 1940, but overwhelmingly favored Thomas Dewey (R) in 1948 (no vote was taken in 1944).
4. The socialists got significant support beginning in the 1920s. In 1912, when the Socialists reached their peak in the actual vote with 6%, they got only 3% of the Harvard vote. In 1920, the actual vote for the Socialists fell to 3%, but Harvard support rose to 6%. In 1932, Norman Thomas (Socialist) got 2% of the actual vote but 19% of the Harvard vote, almost equal to FDR. In 1948, Thomas got only 0.3% of the actual vote but 7% at Harvard.