I don't see that it's massively different than your standard troop deployment on domestic bases; it's just that they're organizing specific training for specific units allocated for disaster response. If some sort of attack or natural disaster did occur, you'd want a decent-sized force that was already prepared to handle it. So long as the troops aren't participating in any conventional law enforcement duties, I don't see how the eroding-civil-liberties argument is anything more than fearmongering.
This is correct. As I mentioned, in a biological warfare case, there are only two institutions currently qualified to handle this: United States Army Medical Research Institute of Infectious Diseases (USAMRIID) and the Center for Disease Control (CDC). The military arm has been around for quite a long time (since the 50's) and has even been showcased in books like The Hot Zone or (incorrectly portrayed) in movies like Outbreak (loosely based on The Hot Zone). This is due to the extremely specialized nature of the diseases in question and knowledge required to handle them, the cost of equipment required to isolate, diagnose, quarantine, and protect adequately (Bio-Safety Level 4 research is not cheap; my local hospital university is still trying to acquire funding to create its own BSL4 lab), and so forth.
Biological warfare is a legitimate terrorist concern. Likewise, you have the United States Army Medical Research Institute of Chemical Defense which has a similar responsibility, but on the chemical warfare front.
To answer the general fear that this is somehow violating laws, here's a Q&A period from one of the previous directors of the CDC, Dr. Frederick A. Murphy:
Q: There are a number of issues concerning the response to an epidemic raised by both "The Hot Zone" and "Outbreak". How well did these describe the interaction of the various agencies?
A: The movie Outbreak created some false impressions. The law in our country gives the responsibility for epidemic management to state health departments, with these agencies calling the CDC when they need help. CDC has no authority to go into a state except by invitation. The Army could be called in by a state health department, but to my knowledge this never has happened.
In the Reston incident, the Virginia Health department and the CDC took over the human health side of the episode and the Army, at the request of the monkey import company, took over the animal side. It turned out after lots of surveillance of animal caretakers and their families that there was no human disease, but there was plenty of monkey disease. The Army's role involved depopulating the monkey colony. So the movie Outbreak, where the Army takes over, is rather fictional.
Source:
http://www.accessexcellence.org/WN/NM/interview_murphy.phpYou need experts with the budget to handle necessary concerns. State governments typically do not have the resources or capabilities to deal with nuclear fallout, chemical or biological warfare, etc.
