Yeltsin's December 1992 compromise with the seventh Congress of the People's Deputies temporarily backfired. Early 1993 saw increasing tension between Yeltsin and the parliament over the language of the referendum and power sharing. In a series of collisions over policy, the congress whittled away the president's extraordinary powers, which it had granted him in late 1991. The legislature, marshaled by Speaker Ruslan Khasbulatov, began to sense that it could block and even defeat the president. The tactic that it adopted was gradually to erode presidential control over the government. In response, the president called a referendum on a constitution for 11 April.