This case involves a dispute between Luxtona, as a former shareholder of Yukos (an energy company), and Russia, which is alleged to have violated certain provisions of the Energy Charter Treaty relating to the protection of investments, including Luxtona's investment in Yukos.
 In this motion, The Russia Federation seeks to disqualify
Professor Stephan from serving as an expert witness on questions
of Russian constitutional and statutory law. There are two
grounds for the motion:
(1) bias; and
(2) lack of qualifications.
 Both sides agree that the admissibility of Prof. Stephan's evidence should be determined now, so that Luxtona Limited may submit evidence from another expert if Prof. Stephan's evidence is excluded.