双方为避共产扩张之嫌，才没立即投怀送抱

据我所知，德克拉克是在柏林墙倒三个月不到，共产体制分崩离析不成威胁之后（如你所说，自顾不暇），才释放曼德拉的。曼德拉和一贯支持他暴力反抗的苏联对这一点心知肚明，双方为避共产扩张之嫌，才没立即投怀送抱，以免危及随后废除种族隔离制的谈判。请见：

South African History Online

http://www.sahistory.org.za/topic/union-soviet-socialist-republic-ussr-and-anti-apartheid-struggle?page=3

A non-event: Mandela and Moscow

With the release of Nelson Mandela in February 1990, and his visits to many capitals of the world, the possibility of his visit to Moscow became an issue with both the ANC and the Soviets. Yet, Gorbachev, according to Shubin, was overly cautious about being seen to expand communism while he was wooing the West. Gorbachev extended an invitation to Mandela but somehow the two sides never agreed on an appropriate date.