“The young being leftists is new ...”
I would beg to differ. The young of the 60s/70s were generally lefties; there was a brief respite wrought by Reagan, then back to form with Clinton. Unfortunately, the lefties of the 60’s/70’s are now called the Administration.
Then why were they voting Republican? The only time the Democrats the youth vote in their time, was after Watergate, when Carter won 51%
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 under 30 age group (without boomers) 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.