This country has faced a biological barrage in recent years. The potentially lethal threats have included HIV, anthrax, SARS, monkey pox, avian flu and E. coli. Now a frighteningly virulent strain of TB has joined the list.
The nation's first line of defense against these assaults, the Centers for Disease Control and Prevention, is once again in the spotlight and facing questions about its handling of this latest medical alert. But an even larger question is often debated when it comes to the CDC -- the extent to which it is an agency influenced by politics.
For most government organizations, political influence is taken for granted. Yet the public is reluctant to think of the CDC that way. It enjoys a reputation for being independent and is among the government's most trusted institutions. In fact, in a Harvard School of Public Health survey in 2005, people gave the CDC higher marks than other health agencies with a 76 percent positive job rating.
Don Kettl of the Fels Institute of Government at the University of Pennsylvania explains that the public thinks of the CDC as "composed of and run by scientists and generally caring for the public health. There's no Republican or Democratic way to give somebody a flu vaccine."
But partisanship still may play a role.
Consider some recent history: In 1995, the CDC did extensive scientific studies of firearm injuries which led it to conclude that guns should be considered a public health threat and regulated in that context. The following year, Republicans in Congress and gun rights advocates sought vigorously to reduce its funding.
Last year, the CDC agreed to a politician's request that it insert two pro-abstinence speakers at a national sexually-transmitted-disease-prevention conference in Florida. It also removed panelists who would have discussed links between abstinence-only programs and rising STD rates.
And in April of this year, the Atlanta Journal Constitution reported that the CDC had failed to fill nearly half of its 304 overseas positions. The newspaper acquired an internal CDC memo which worried about the vacancies since the threat of a bioterrorist attack from abroad "fuels the urgency to make overseas assignments in a timely manner."
According to the paper, the memo said one reason for the delay was "an additional bureaucratic layer that requires CDC foreign postings be approved by a senior political appointee's office in Washington."
The CDC did not respond to ABC News' requests for comment.
Jeff Levi of the Trust for American Health worries that politics does shadow the CDC.
"I think CDC is designed and structured to be a public health agency that really focuses on science as the basis for its policy and decision making," he said. "Unfortunately, particularly over the last six years, we've seen more and more intrusion of politics on some of their scientific decision making."
Dr. James Mason, who ran the CDC from 1983 to 1989, acknowledges that politics has always been a force to be reckoned with at the agency but that "should come as no surprise."
Mason points out that the CDC is under the Department of Health and Human Services, whose secretary must be confirmed by the Senate.
"Of course you are going to have some political oversight and political influence," he said. "It's inherent and necessary."