How old was Mikhail Gorbachev when he ecame a member of the Politburo ?
To make matters worse for Chernenko , he did not have control over the Politburo ; both Andrei Gromyko and Dmitriy Ustinov were both very independent politically , and the Politburo still contained several leading Andropov protégés , such as Gorbachev , Vorotnikov , Solomontsev and Heydar Aliyev .