also potentially be capable of countering strategic ballistic missiles, not just theatre ballistic missiles. The Clinton administration began negotiations with the Russians in 1993 to make amendments to the treaty. After much discussion, Presidents Clinton and Boris Yeltsin signed addendum to the treaty on September 9, 1997. According to these new agreements, the treaty permitted missile defense systems to have a velocity up to 5 km/s as long as it had not been tested against targets traveling faster than 5 km/s. The 1997 agreement were eventually ratified by the Russian parliament on May 4, 2000 (along with START II treaty). However, it was opposed in the US Senate by some Republican senators led by Jesse Helms. As a result, Clinton never submitted the agreement to Congress, fearing that Helms would stall their ratification or defeat it outright. Successor states to the Soviet Union Although the Soviet Union ceased to exist in December 1991, in the view of the U.S. Department of State, the treaty continued in force. For the purposes of the treaty, Russia was confirmed USSR's successor state in January 1992. Belarus and Ukraine were treated as successors at the ABM review conference in October 1993 and Kazakhstan was added as a successor shortly after. Belarus, Ukraine and Kazakhstan became regular participants at ABM treaty meetings known as Standing Consultative Commissions. An additional memorandum of understanding was prepared in 1997, establishing Belarus, Kazakhstan, the Russian Federation, and Ukraine as successor states to the Soviet Union, for the purposes of the treaty. The US considered only extending the obligations to these countries, and not all, as only these ones had significant ABM assets. As the ABM treaty allowed for only a single ABM deployment, the State Department deemed that only a single ABM system would be collectively permitted among Russia, Ukraine, Kazakhstan and Belarus. In the United States, there was a debate on whether after the dissolution of the USSR, the ABM Treaty was still in effect. A month after the USSR's dissolution, President George H. W. Bush affirmed the ABM Treaty and regarded Russia as USSR's successor. Russia also accepted the ABM Treaty. Later on, President Clinton would affirm the validity of the treaty, as would President George W. Bush (before he terminated it). However, some Americans (mostly conservative Republicans) argued that the treaty was not in effect because the USSR had no successor state. This was deemed inconsistent,