I believe the answer is: They worried about having to take part in future wars.
At that time, the united states senates prefer to take the position as a neutral force that want to avoid any intervention toward other countries' problems. This stand is taken away the moment the Japanese army decided to initiate an attack to the pearl harbour.
Europe mostly
north america
south america too
Soviet Union DID NOT join, it started the Warsaw pack
<u>Answer:</u>
The quarantine speech was presented by president Roosevelt where he called the positive endeavours to quarantine the land hungry dictators. He did not directly mention any country, although the speech was focused on the Nazi Germany, the Japan's empire, and the Kingdom of Italy.
He mentioned in his speech that the spread of violence and war is like a contagious disease, he said that, when a few members get infected by a contagious disease, the country tries to destroy them, the same treatment should be done with them who try to break a country's peace through violence.