As the NSC's Soviet/Russian affairs expert under George H.W. Bush, Condoleezza Rice advised the president on dealings with Boris Yeltsin during the chaotic transition from the Soviet Union to the Russian Federation. President Bush was 'captivated' by Rice and relied heavily on her analysis for understanding both Gorbachev and the rising Yeltsin. Rice's expertise on Russian affairs — rooted in her PhD work under Josef Korbel at the University of Denver — was the foundation of her value to the Bush family and the gateway to her later career as a broader foreign policy generalist.