Another historic use of this policy is whether the United States would retaliate to a chemical or biological attack with nuclear weapons ; specifically , during the Persian Gulf War . Related is the notion of a nuclear umbrella . Some commentators believe President Barack Obama broke US policy and damaged U.S. interests by failing to take sufficient action against the regime of Bashar al-Assad for its Ghouta chemical attack on civilians in the village of Ghouta near Damascus on August 21st , 2013 . President Barack Obama had used the phrase " red line " in reference to the use of chemical weapons on August 20th , just one day prior . Specifically , Obama said : " We have been very clear to the Assad regime , but also to other players on the ground , that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized . That would change my calculus . That would change my equation . " Since a passing a 1987 law , New Zealand has banned all nuclear powered means of war , whether nuclear weapons or nuclear powered propulsion from its sovereign territory ; thereby making it a military nuclear-free zone . New Zealand has not banned civilian nuclear energy , but it is no longer used there and the public is quite opposed , thereby making it a '' de facto '' nuclear-free country . This ban includes its territorial waters as per the United Nations Convention on the Law of the Sea
Ghouta chemical attack
Ghouta chemical attack
Policy of deliberate ambiguity