Why were college towns so Republican before the 70's?

[SingingAnalyst]

Probably because most were located in rural, Protestant, northern areas. Perhaps, and this may be a stretch, because some colleges (Princeton for example) were founded as centers of religious instruction or at least as an alternative to "liberal" universities (Harvard). Today the largest Republican university county I know of is Greenville Co, SC, home of Bob Jones University. As BJU slowly joins the mainstream (they dropped their rule against interracial dating in 2000) will the county become more like the country or at least more like SC?

1952: Stevenson 47% Eisenhower 53%
1956: Stevenson 43.5% Eisenhower 39.5%
1960: Kennedy 38% Nixon 62% (Kennedy tanked for obvious reasons)
1964: Johnson 37% Goldwater 63%
1968: Humphrey 21.6% Nixon 52.9% Wallace 25.5%
1972: McGovern 17.4% Nixon 79.6% (in a university town!)
1976: Carter 47.3% Ford 51.5% (Chancellor Bob Jones was sharply critical of Betty Ford, but supported Ford over Carter)
1980: Carter 40% Reagan 57.4%
1984: Mondale 26.4% Reagan 73.1%
1988: Dukakis 28.6% Bush 70.8%
1992: Clinton 30.4% Bush 57% Perot 12.1% ("to vote for Clinton is to sin against G-d")
1996: Clinton 34% Dole 60% Perot 6%
2000: Gore 32% Bush 66%
2004: Kerry 33% Bush 66%
2008: Obama 37% McCain 61%
2012: Obama 35% Romney 63% (clearly these fundamentalist Christians had no difficulty voting for a Mormon)

[SingingAnalyst]

Wealth and liberalism, before the parties were so unified ideologically. In 1978, admittedly a long time ago, MA and MI had liberal Republican vs conserative Democrat gubernatorial elections.

MA: King (D) 52.3% Hatch (R) 47.4%
Cambridge: King (D) 40.6% Hatch (R) 59.4%
Amherst:  King (D) 15.0% Hatch (R) 84.8%

MI: Fitzgerald (D) 43.2% Milliken 56.7%
Ann Arbor: Fitzgerald (D) 24% Milliken 75%
East Lansing: Fitzgerald (D) 13% Milliken (R) 86%

In both states, the Dem did relatively well in poor, white, working class areas, and the Republican won a larger than usual share of the Black vote.