Here's one I think we've overlooked so far.
Teddy Kennedy was basically offered the 1968 Democratic nomination for President. The delegate counters figured he'd stop Humphrey on the first ballot, and win on the second.
California, Illinois, and New York were all for him. Mayor Daley didn't like McCarthy, Jesse Unruh (leader of the California delegation) didn't like Johnson and neither wanted Humphrey.
Half of Pennsylvania's delegation, and a varying number of other delegates from other states (including a dozen Southern delegates) would be shaken loose by Teddy Kennedy throwing his hat into the ring.
In the general election Teddy Kennedy was five million votes ahead of Humphrey—more than enough to beat Nixon.
So.
President Edward M. Kennedy in 1968? What happens?