One of the supposed rationales for government-run "universal health care" is that Americans with pre-existing conditions are unable to get insurance coverage.
However, in a 3/10/2011 blog post at Forbes ("The Road to Socialized Medicine Is Paved With Preexisting Conditions -- Part 2"), Don Watkins and Yaron Brook of the Ayn Rand Institute discuss the fact that insurance is a service that must be created by rational thought and effort. Compelling insurers to cover all patients regardless of pre-existing conditions would violate the rights of those who provide that service and would destroy the remnants of the private insurance market.
The current problems of pre-existing conditions are caused by bad government policies that unfairly favor employer-based health insurance, which results in insurance being artificially linked to one's job.
Watkins and Brook also discuss some ways in which a free market for insurance service would address the issue of pre-existing conditions. In particular, they linked to an excellent public policy paper published by the Cato Institute, "Health-Status Insurance: How Markets Can Provide Health Security" (PDF and HTML versions).
For more on how free markets can address the issue of pre-existing conditions, please also see my article in the Fall 2009 issue of The Objective Standard, "How the Freedom to Contract Protects Insurability".
Instead of more government controls over health insurance, we need to repeal the existing ones and let insurance companies operate in a fully free market.