The U.S. government has been engaged in war after war since it's inception. There has hardly been a time when the U.S. is not at war. This may be going back to Eisenhower's
warning about the military industrial complex, but whether we had the industrial complex or not the U.S. found a war—sometimes justified as World War II or sometimes a concoction like Bush's illegal Iraq war. Take a look
here to count up the wars. Click on the headline to read a Congressional Research Report on declaring wars and authorizations for war.