WARNING SIGNS — Long before a gunman pumped bullets into a UnitedHealthcare executive and was hailed as a folk hero by a startling slice of the American public, the longtime head of the American Board of Internal Medicine found himself increasingly aware of — and alarmed by — the creeping distrust of American health, science and medicine.

The murder of UnitedHealthcare CEO Brian Thompson in midtown Manhattan is a tragedy of immeasurable proportions.

Americans have increasingly negative opinions about the U.S. health care system, according to the results of a new poll. The survey released on Wednesday by The Economist/YouGov found that a 54 percent majority of respondents had a "very" or "somewhat" unfavorable view of the American health care system.