There are many cases that the United States of America can be accused of manufacturing war. This is definitely the case in Iraq and Afghanistan because there was no reason to go to war. Especially in Iraq because we went to war on the basis that Iraq had weapons of mass destruction. However, they did not have those weapons.
The United States hasn't manufactured a war since the Iraq War started in 2003. Bush Jr wanted to finish the job his father started, so he claimed Saddam Hussein had weapons of mass destruction. Conspiracy theorists believe World War II was manufactured when FDR allegedly "let" Pearl Harbor happen. The same is true of 9-11 conspiracies. The Vietnam War and even Korea were manufactured wars in the name of trying to defeat communism. War is big business as World War II got America out of the Great Depression.