The Reagan Doctrine was, in a sense, an important response to the Brezhnev Doctrine of the Soviet Union. First explained in President Ronald Reagan's February 1985 State of the Union Address, Reagan said:

"We must not break faith with those who are risking their lives...on every continent, from Afghanistan to Nicaragua ... to defy Soviet aggression and secure rights which have been ours from birth. Support for freedom fighters is self-defense."

The Reagan doctrine aimed to justify American support of the Contras in Nicaragua, the Mujahadeen in Afghanistan and Jonas Savimbi's Unita movement in Angola, among other anti-communist resistance groups.

The doctrine was supported strongly by foreign policy analysts at the influential, conservative Heritage Foundation, who helped define and politically advance it.

Critics of the doctrine argued that it would lead to so-called blowback, inflaming Third World hostilities to the United States.

But conservative advocates of the doctrine argued that it served the foreign policy and strategic objectives of the United States and was a Cold War moral imperative against the former Soviet Union, which Reagan and many of his supporters labeled an "evil empire."

In the end, conservative advocates won the argument, and arms flowed to the contras, Savimbi's Unita and the Mujahadeen. Nevertheless, blowback happened after all, however from an unexpected side, as the case of Osama bin Laden shows.