Article: Tito's greatest strength, in the eyes of the western communists, had been in suppressing nationalist insurrections and maintaining unity throughout the country. It was Tito's call for unity, and related methods, that held together the people of Yugoslavia. This ability was put to a test several times during his reign, notably during the Croatian Spring (also referred as the Masovni pokret, maspok, meaning "Mass Movement") when the government suppressed both public demonstrations and dissenting opinions within the Communist Party. Despite this suppression, much of maspok's demands were later realized with the new constitution, heavily backed by Tito himself against opposition from the Serbian branch of the party.[citation needed] On 16 May 1974, the new Constitution was passed, and the aging Tito was named president for life, a status which he would enjoy for five years.

Question: What was referred to as the "Mass Movement"?
the Croatian Spring