Josip Broz suppressed Maspok and, at the same time, made a great concession to Croatian nationalism. Broz allowed use of the Croatian language in Croatia and confederalized the Yugoslav Constitution in 1974, giving veto rights to the Yugoslav republics when attempting to change the Constitution. The 1974 Yugoslav Constitution was a source of a great dissatisfaction and concern of the Serbs in Yugoslavia. The Croatian Communist League leadership, Dabčević-Kučar, Tripalo, and Pirker were forced to resign from their state and Communist League positions and some of the Maspok leaders were arrested and imprisoned. Among the arrested Maspok leaders were Franjo Tuđman and Bruno Bušić.