Why do you guys keep stopping at "contribute to society"? If you're going to make any distinction it should be "how MUCH contribution to society".
But, that's the problem.
Society isn't some sort of static entity which would allow for an absolute definition of what enough contribution is. When the founding fathers started the country, being a land owner was quite sufficient - because most land owners were self-responsible agrarians, not urban landlords (as is the case today).
So, the criteria for citizenship would need to not only take into account such things as industry and cultural change, but it should allow for people of different professions to become citizens (and therefore vote). The idea would be to allow localities to select the people in their own community who can be citizens, both for a cohesive local community and the ability to help make the local decisions as well as to make the decisions at a national level.
It's complex, and I can't figure out a way to effectively do so without disenfranchising a lot of good poeple, without moving the selection criteria to subjective measures at the local level. But, of course, that would end up being a problem, too, with places like Chicago making everyone a citizen just so they can vote in the Democrat primaries... Only solution I have to that is to make ownership of one's own home an absolute criteria if a person/family is not a primary producer. Unfortunately, that isn't really a solution, and it's gone full circle to what the forefathers intended.
I'd really like to get my hands on the documents the forefathers wrote which discuss this topic...
Your say in government should then be ranked on how much service and wealth you invest.
Asolutely not! That would, in essence, be elective feudalism (or something similar) - but without the necessary requirement of the rich to provide something in return. That would be horrible without completely destroying the institution of the "corporation" as it is known today. That is, unless you think it's reasonable to have laws like "every household must use a certified and licensed Microsoft OS for their household appliances, and any household running an alternative will be fined $3,000" - or something similar.
That's the original subject we are discussing here. If you want to make it fair, go all the way.
Again, no, let me just say: this is just so much nonsense. Our founding fathers put an unprecedented amount of responsibility and freedom upon the common man, but it was also clearly stated that all men are created equal. No, it doesn't mean all men are of the same ability, but all men are to be treated equally under the title of government. Giving one man 5 votes and another 1 - even though they're both contributing to the society to the best of their ability - is not what the founding fathers intended. Therefore, they set a minimum requirement for voting, initially: land ownership. They also played with other ideas - literacy, military service, professional associations, a certain level of income - and on and on. Yet, none of them worked long enough or had enough support, because the desires and demands of the populace outweighed.
So that's why I think local selection of people for citizenship by a board or series of boards or people chosen randomly from the populace would be appropriate. (We do the same thing to determine whether someone's going to jail - why not whether or not someone can vote?) Nationally suggested criteria ("pay particular attention to those who own land, are involved in their community, etc. but keep in mind that we want someone who is a net contributor to society and has the welfare of the community and country in mind, not his own self advancement - so moguls would be on equal standing with those who do crack cocaine") but ultimately the local boards of citizens would get to decide directly.
Oh, and by the way (for the person who said that we're a "capitalist democracy"): no, we're not. We were founded as a democratic republic. There is a huge honkin' difference there: democracy is the tyrany of the majority, and a democratic republic attempts to balance out the will of the populace and normalize the extremes.
ETA x2: And, I should note that under this plan I would likely be exempted from citizenship at this time, were I to apply, due to my current lack of gainful employment, lack of property ownership, etc. - though in my idealized society, there would be a local militia which I could participate in (or I could assist at the library, sit at the county clerk's desk a couple times a month for a couple hours, volunteer at the nursing home, etc.) and gain the social standing which would allow me for inclusion for citizenship. Ideally, there would be enough of such contribution from people attempting to get and retain citizenship that there would be little to no need for many of the "community service" let alone "government service" jobs any longer.