national guardsmen shot and killed four students
Conservatives opposed large central government.The conservative views of government are contrary to the liberal views because conservatives want to work harder and to spend their earned money whereas the liberals are less willing to work hard and to spend their money.
Retiree's are older, and typically politically conservative, so the large migration of retirees to Arizona, Florida, and the other 'Sunbelt States' led to those states becoming conservative as the population of retirees increased in the warm-weather states..
the political power of the sunbelt increased
The Soviet Union felt it had to have at least parity in arms with the US. The US felt the same way about the Soviet Union.
This led to the so called arms race.
The US was and is more economically sound and stable, effectively richer.
The Soviet Union spent more and more on arms, far more than it could afford, thus becoming effectively bankrupt.
His public speaking skills elevated his popularity.