Who stops the United States Government for violating its OWN antitrust laws?

When Obama care takes effect in 2013, there will be little the private health sector can do to inhibit the government's cannabalization of the private health care market. Inevitably, private carriers will be forced out of business against the government's "not-for-profit" business model that derives "profits" from tax payers and NOT premiums otherwise collected by private carriers. In effect, the U.S. Government can intercede in ANY private industry it sees fit to "regulate" in the name of "fairness". Nationalization of any private sector industry does not work. No government on the planet can line up an effective business model against the private sector, not one. Yet, ideologues never stop in their quest to establish monopolies (i.e., nationalization) and tell their citizens that in the end it will be good for them. Really? Think about that. Why don't we let the likes of Microsoft or McDonalds dominate their respective markets? Why? Because it isn't fair? Well, if its ok for governments to usurp private markets based on their ideologies, why not any private company as well that can provide the same service better than the others? After all, isn't that why Obama implemented "ObamaCare" in the first place?