Gorbachev was possibly the most stupid leader the USSR ever had. I've read his memoirs: two bits of evidence of his stupidity - first, he had worked within the Soviet system for years, yet when he took office, he thought it was still flexible enough to adapt to changing circumstances, when any one with half a brain could see the country was being strangled to death by it. Second, he tried to make Russia go dry. This had the predictable consequence of creating a huge market for moonshine and subsequent deaths from said homemade liquor.
Regards, Ivan