"Fringe" is a Thursday Fox show that is a decendent of "The X-Files". Anyway, this upcoming episode seems to be about neo-Nazis who develop a poison gas which only kills Jews. Does Alex have a part-time gig as a script writer?

Though I, of course, haven't yet seen it, my guess that to work it would have to be a dual poison. The first dose makes a victim susceptible to the next. Someone without the first dose would not be effected by the second. A bit cumbersome unless you needed to get your personnel in place to take over. An example: The first dose is put in the water coolers and coffee urns of a bank before it opens; then a gas is released by robbers to incompacitate the bank employees so that a robbery can take place. Though this explanation probably isn't correct for the TV show which aims for something more outlandish.

The Warlord