If Goldwater won in 1964

[NewYorkExpress]

There'd be no Great Society (at least not in the sense that Medicare would be a thing). Goldwater probably would sign the Civil Rights Act of 1964 and the Voting Rights Act of 1965, as he personally agreed with both bills. While he didn't support Federal intervention in that way, I think he'd intervene to get them passed to keep his chances of winning renomination in 1968 (where he'd need support from Northeastern Moderates).

He'd also almost certainly fire J. Edgar Hoover. I can't picture Goldwater, a civil Libertarian on most issues, approving of Hoover's FBI spying on American citizens, so unless Hoover has great blackmail on Goldwater, he'd be out of a job.

We'd be heavily involved in Vietnam, even more so than LBJ did IRL, and Goldwater would take the advice of Curtis LeMay, and would probably break the Nuclear Taboo in North Vietnam.