Yes, we should have stayed out of both wars
FDR was hell-bent on dragging America into the conflict in Europe. Most Americans were against entering WWII. Provoking a fight with the Japanese was his best chance to so. FDR knew that the Japanese were planning to strike Pearl Harbor because he had been given decrypted diplomatic and naval message traffic in advance of the attack (William H. Friedman broke the Japanese "Purple" diplomatic cipher and Agnes Meyer Driscoll broke "Code Book D" of the Kaigun Ango system in 1940). FDR sat on the information in order to rally American support for entering the war. FDR allowed thousands of American sailors to die to promote his political agenda. The fact puts him on the level of Dubya in my eyes. For all the good that he did, FDR was a warmonger.
The founding fathers were clear about the use of military force. They did not want the U.S. to have a standing army. The only reason why they supported a standing Navy was piracy.