Mandates, such as the health insurance mandate, do fit within the limits of government intervention. The free market system that is created by the insurance mandate allows for competitive prices and for all people to have health care. This extends the advantages of the free market to U.S. Citizens and does not cause the government to overstep its limits.
No, health insurance mandates do not fit within the limits of government intervention, because the commerce clause of the constitution does not authorize the legislature to compel commerce. The commerce clause allows the legislature to regulate interstate commerce, but it does not allow the legislature to make people buy a certain product.