http://en.wikipedia.org/wiki/Starship_Troopers
Just take a look.Seriously speaking,what do you think is the validity of having only those who have served society in some capacity having the right to vote,while being restricted from other segments of society?
Well quite honestly this has happened in the old republic roman days and greek days.Where u have to be a land owner to have your votes count and all land owners and citizens have to serve in the military.
But that was before the age of professional armed forces.It's hard to say if it is still relavent today.
Though i dont mind those serving or have served getting some extra goodies like tax breaks and stuff.
Well,true,tax breaks would be very welcome,but in modern terms I wouldn't want the voting rights to be restricted to an exclusive group.It would concentrate too much power in that segment of society,and lead to an imbalance.