The army and military industries are huge employment and research organizations. Not efficient ones in the latter case, but there you go. You'd have to re-targ

The army and military industries are huge employment and research organizations. Not efficient ones in the latter case, but there you go. You'd have to re-target all that employment and spending somewhere to make up for the hole, like, say, health and energy. Unfortunately other countries around the world may not make the same decision as you and the US would fall behind in certain capabilities, which may be important to have at some point.