Although ronald reagan had been a vigorous cold warrior throughout his political career, why was he able to bring about a remarkable easing of cold war tensions? (ch. 30)

Ronald Reagan was largely known to be an anti-communist and a fierce Cold Warrior, but he also took a big role in ending the Cold War.

Despite that Reagan took a policy called Reagan Doctrine, that was a policy to weaken the Soviet Union by aiding anti-communist resistance movements and manipulating governments in a series of places such as Asia and Africa. 

With this series of movements, Reagan was able to weaken the Soviet Union by forcing them to invest in military and increasing social and economic problems internally. With that, Reagan found in Gorbachev a good ally and signed the nuclear arms reductions agreement ending the Cold War.