The Inoculation Effect

Why Syria Felt Emboldened to Use Deadly Gas, Newsday, April 15, 2018. "Despite their fearsome reputation, most weapons of mass destruction — even the conventional ones — are not used often. Like a vaccine, their first use seems to inoculate the world against further uses. But in Syria — struck by Western missiles early Saturday — the inoculation effect against poison gas has been failing. And so is the U.S. policy that contributed to it."