Havel said that his most important accomplishment as president was breaking up the Warsaw Pact ( interview with Karel HvÃ Å 3\/4 Ä ala included in To the Castle and Back ) . In an interview with Karel HvÃ Å 3\/4 Ä ala ( also included in To the Castle and Back ) , Havel stated that he felt his most important accomplishment as president was the dissolution of the Warsaw Pact .