In 1990, Ljajić was elected Secretary General of the Party of Democratic Action of Sandžak as one of its founders, a branch of the SDA in the Republic of Bosnia and Herzegovina, aimed at gathering Bosniaks in Serbia. In 1993 he left the party and with dissidents formed the Sandžak Democratic Party, criticizing Sulejman Ugljanin for being an extremist and endorsing separatism from Yugoslavia in an effort to join an enlarged Bosnia dominated by Bosnian Muslims.