Donald A. Donahue, DHEd, is the Director of the Health Policy and Preparedness Program at the Potomac Institute for Policy Studies.  In an op-ed for the Washington Times, he writes that as the nation's attention shifted to the killing of the world's most-wanted terrorist, Osama bin Laden, a series of disturbing events on our home soil provided a reminder that the threat of terrorism is far from defeated. In this case, powder-laden envelopes were being discovered at a number of schools.  While the powder appears to have been harmless, the ability to carry out this perhaps "hoax" attack reveals that we are still very vulnerable.  Click here to read the article in full.