How did the Cold War influence America at home?

At home, the most important impact of the Cold War was to
create a fear of communism.  This fear was manifested most clearly in the McCarthy Era,
but it was not limited to that time.

During the Cold War,
Americans feared that communism would take over the world.  Sometimes, they feared that
it would take over from within as American communists undermined US commitment to
democracy.  This led to such things as the McCarthy era hunts for communists within the
US.  Sometimes, they feared that it would take over through military force.  This led to
a situation in which Americans supported increased military spending and military
actions around the world to contain communism.

Overall,
then, the Cold War made the US fear communism and take steps to prevent communism from
taking over either by force or by subversion.