You may not buy the idea about a Republican Reagan breaking the USSR, but that is just what happened plain and simple. The Russian people were getting a taste of Western living and wanted what we had (cars, appliances etc.). Russia just couldn't do both have a arms race and keep the people happy. The "iron fist had softened. So we did break the USSR. Of course they could have dragged the "Cold War" on, but at the cost of possibly another revolution. Gorbachev, saw that possibility and surrendered so to speak.
Credit to Gorbachev....but he was pushed, coaxed, cornered, cajoled, encouraged, and basically hurried down the road with carrot and stick by none other than Ronald Reagan.
Reagan had no great intellect, but he BELIEVED........Mitterand said of him that what he did not comprehend through intellect he understood through instinct.