clipped from: www.americanthinker.com   
Individuals even perform shared tasks. If you and I decide to cooperatively lift a heavy bag of cement, you must lift your half of the bag and I must lift mine. We do not literally share lifting the bag. I lift half and you lift half.  If I refuse to do my "share," you are stuck lifting the entire bag. If you cannot physically lift the bag alone, then the bag stays put. If the bag is too heavy for you to lift by yourself then you cannot control the movement of the bag. Not even if you are a liberal. That is the way human action works in this world.

What holds true in lifting cement bags holds true in social contracts. If you and I contract to "share" the costs of "public" housing for the indigent, you will pay half and I will pay half.  If you refuse to pay your half, then I am stuck with the entire bill. If the price of the housing is too expensive for me to pay, or if I refuse to pay, then a fellow citizen will not be housed for free. That is the way economics work in this world.