The Iranian revolution and the Soviet invasion of Afghanistan in December 1979 led the US to hurriedly announce the Carter Doctrine in January 1980. This declared that Gulf oil was a ‘vital interest’ of the US, and that America would deter or respond to ‘outside’ threats to Gulf security; it included this ringing assertion: An attempt by any outside force to gain control of the Persian Gulf region will be regarded as an assault on the vital interests of the United States of America, and such an assault will be repelled by any means necessary, including military force.
