( I am a former Foreign Service Specialist with the US State Department, and I spent the last ten years in Iraq/Afghanistan). The US State Department keeps a security watch on every country in the world. And the security situation is published, on their website. Anyone can contact the State Department, and get a security advisory on any nation in the world.
If you are traveling to Canada, or Western Europe, or Japan, you should exercise caution, but you can generally travel to these countries in equal or better safety, than you will experience in the USA. With the Ebola situation in West Africa, you should take precautions against visiting any area where the disease is. If you are traveling to countries where there is Malaria, the state department will advise you about malaria prevention.
International travel is serious business, whether you are on business or pleasure. When you are in a dangerous area, where there is political unrest, you should always check in with the US Embassy or Consulate, when you are there, to get the latest security advisory.