Robert Heinlein had an even better and simpler idea.
Only retired military (and retired long-term non-elected civil servants) would be allowed to vote. These being the only people who have demonstrated that they are willing and able to put the welfare of the country ahead of the welfare of their tribe, family, or selves.
This class would also be the only people allowed to be teachers, policemen, judges or elected officials among a few other ‘protected’ jobs.
Everyone else would be a resident or non-voting citizen.
Simpler yes, better no. Those are all people conditioned to getting a government paycheck. Who wants only government people voting on who runs the government?
Oh, and I can disprove his theory with two simple words.
John McCain.
Need more words?
Jack Murtha.