My first vote was for Nixon in '72. And I had the chance to tell him that to his face in a hotel lobby in Prague when he was traveling in Eastern Europe as an "elder statesman", the year before he passed away. If you were "heartless" to vote for Reagan in '80 my vote as an 18 year old for Tricky Dick must make me a prince of darkness.
Nixon won 52% of the 18 to 29 year old vote in 1972.
In 1968 the Democrats won 47% of the (21) to 29 year old vote, in 1972, they won 46% of the 18 to 29 age group, in 1976, after Watergate, and with the weak, moderate (and under suspicion) Ford, against what appeared to be a social conservative Democrat with a strong military back ground, the Democrats picked up 51% of the 18 to 29 year old vote.
In 1980 Democrats got 44% of that age group, 1984-40%, 1988-47%.
It wasn't until 1992 that the age group became a Democrat voter group, George W. did get 46% and 45% though.
The 66% that Obama won, is unprecedented and doesn't bode well for the future.