Article 5 of the Egyptian constitution and the Political Parties Law of 1977, amended in 2005, regulates political parties and their activities. Approved by a plebiscite, the 1977 law prohibits any propaganda directed against the principles of the socialist democratic system and the principles of the 1952 and 1971 revolutions. In June 2005 the Egyptian parliament introduced basic changes concerning the parties’ financial resources. Political parties could no longer be dissolved, or prevented from political practice by the "political parties committee." Such a decision now requires an investigation by the public socialist prosecutor proving that the political party in question has violated or gave up one of the general conditions that justify the formation or persistence of any political party. Despite a constitutional ban against religious-based parties, the Muslim Brotherhood constitutes a significant political force in Egyptian politics.