how did western democracies respond to the spread of communism in europe and around the world?

Because of the spreading of the communism in Europe and around the world, the Western democracies formed a military alliance, NATO. NATO was formed do that the Western democracies can protect their interests, be it territorial, economic, or zones of influence. The response was very aggressive actually, as once NATO was formed, the Western democracies started to get themselves involved in military conflicts in numerous places around the world where the communism was spreading. The communist countries responded adequately though, and they formed an military alliance of their own, the Warsaw Pact, leading to constant tensions in the following decades.

i don't know why don't you google it?