With the development of more rapid-response technologies (such as rockets and long-range bombers), this policy began to shift. If the Soviet Union also had nuclear weapons and a policy of "massive retaliation" was carried out, it was reasoned, then any Soviet forces not killed in the initial attack, or launched while the attack was ongoing, would be able to serve their own form of nuclear retaliation against the U.S. Recognizing that this was an undesirable outcome, military officers and game theorists at the RAND think tank developed a nuclear warfare strategy that was eventually called Mutually Assured Destruction (MAD).