Warsaw Pact
On 25 February 1991, the Pact was declared at an end at a meeting of defense and foreign ministers from the remaining member states meeting in Hungary. On 1 July 1991, the Czechoslovak President Vaclav Havel formally declared an end to the Warsaw Treaty Organization of Friendship, Co-operation, and Mutual Assistance which had been established in 1955. The USSR itself was dissolved in December 1991.
Who was the president of Czechoslovakia during the dissolution of the Warsaw Pact? 
Vaclav Havel
On 1 July 1991, the Czechoslovak President Vaclav Havel formally declared an end to the Warsaw Treaty Organization of Friendship, Co-operation, and Mutual Assistance which had been established in 1955.
Warsaw Pact