Which leader had the greatest influence on the end of the cold war?

Answer 1

The cold war ended not because of anything to do with leadership. The cold war ended because the system of government in the USSR finally ran out of steam. To maintain a threatening position when your people don't have enough to eat, when your industry is falling into disrepair, and you are depending on obsolete technology - well, you have to call it a day. Nature is what put an end to the cold war. The gangsters that were calling the shots simply lost the ability to keep up the threat.

Answer Two:

Ronald Reagan, for his fervent pro-capitalism, pro-military, anti-communistic beliefs and Mikhail Gorbachev for his "glasnost" (openness) and "perestroika" (restructuring) are generally credited with the ending of the Cold War. But there is much truth in the first answer.

By any accounts, it was a group effort, and those two were just presiding near the end.