We can't exclude some people who only vote their own interest, because in some way we all do exactly that. But, we can educate people on the universal value of voting America's interest first.
If that were the case there would be little debate in congress about the need to remove John Boehner, in my opinion.
The idea of free elections is only a part of the need to keep a country strong. An Informed and virtuous citizenry must also be a part of that chemistry. In order to instill this into elections it is necessary to test the citizens before they vote, just like we test them before they drive.