Why did the united states assert itself as a world power

Actually it's "He did not want the United States to become too involved in the affairs of other countries."

We must never give in to exaggerated fears and must continueto fight for our rights to express ourselves and not have our movements bemonitored by government.  We must alsoprotect our rights to fair trial that the McCarthy Era tried to destroy.  No one should be subjected to witch hunt orbe branded a traitor or spy without the benefit of a fair trial.  The McCarthy Era played on people’s fears butit also destroyed people’s lives. We must never let that happen again.

Following World War 2, as the Cold War developed and the Soviet Union was gathering allies, there was much fear -- and fear-mongering -- in the United States about the threat of communism.   This time period, from the late 1940s to late 1950s, is known as the Second Red Scare.  This was when the House Un-American Activities Committee (HUAC) was created and when Senator Joseph McCarthy began a campaign of accusations against suspected communists in various sectors of American life.  During the Second Red Scare, many people were targeted -- including especially those in the entertainment industry, journalism, and in government and the military.  The lessons learned from the McCarthy era showed that the freedoms guaranteed in the Bill of Rights must be vigorously defended.  If individual's rights to freedom of speech and freedom of association are called into question, and due process of law is not followed, everything America stands for can come under attack.

A good film you might look for on the subject of McCarthy's fear campaign and how it was overcome is the 2005 movie, "Good Night and Good Luck."  The film shows the efforts of journalist Edward R. Murrow to battle against McCarthy's excesses and unfounded accusations.  It was especially through the efforts of Murrow that McCarthy's excessive actions were stopped.