[lastchance]

I postulate this: The government should provide services that it can do better than the private sector/individiuals, and not do anything that it can't do better than the private sector/individuals.

Assuming you agree with the above, the most important question is "what can our government do better than we can?"

Situations when the govrenment is better:
1. A program that needs to be standardized and must be consistent across the country. (police, justice system)
2. Central planning required. (roads)

I conclude that the government is most useful when a single, combined effort is more efficient than many individual efforts.

If you think the government should provide a service, you need to prove that a single, combined effort is better than many individual efforts. If you think the government should not provide a service, you need to prove that many individual efforts are better than a single, combined effort.