The United States should cut some of the Department of Defense's budget and dedicate more funding to education. When more people are educated, there are more citizens with college degrees. More people with college degrees won't join the military because they will have better-paying jobs. The military won't need as much money with fewer personnel signing up because of the education money to pay for more college entrants.
The US government spends enough money on education, much more than many other developed countries combined. The problem is what they teach kids at schools. Get rid of social stuff, sex ed, "tolerance", and other such crap. Teach the kids to read, spell, write, and count. Teach them to think.