Marković owed his popularity to the image of new, modern Western-style politician who doesn't shy away from applying make-up before television appearances or starring in television commercials. As such, he quickly became the darling of liberal circles who wanted Yugoslavia to be transformed into modern, democratic federation. Marković also maintained popularity by staying out of increasingly virulent quarrels within the leadership of Yugoslav Communist Party or trying to act as mediator between various republics.
When CPY broke up in January 1990, Marković had only his popularity and the apparent success of his programme on his side. In July 1990, he formed the Union of Reform Forces (Savez reformskih snaga), a political party supporting a reformed Yugoslavian federation. According to a poll conducted by the Federal Executive Council (SIV), this party had support of 14% of the people in Bosnia, and less than 5% in other republics.
This decision was not well received. Borisav Jović, then the President of Yugoslavia, commented
The general conclusion is that Ante Markovic is no longer acceptable or reliable to us. No one has any doubts in their mind any longer that he's the extended arm of the United States in terms of overthrowing anyone who ever thinks of socialism, and it is through our votes that we appointed him Prime Minister in the Assembly. He is playing the most dangerous game of treason.
Jovic's conclusion on Markovic's role
He was no doubt the most active creator of the destruction of our economy, and to a large extent a significant participant in the break-up of Yugoslavia. Others, when boasted of having broken up Yugoslavia wanted to take this infamous role upon themselves but in all these respects they never came close to what Markovic did, who had declared himself as the protagonist of Yugoslavia's survival
Later, his programme was sabotaged by Slobodan Milošević and the Serbian government, and the authority of the federal government was diminished by secessionist moves in Slovenia and Croatia. In the last months of his tenure Marković tried to find compromise between secessionists and those demanding that Yugoslavia remains as single entity. His efforts, although favoured by new democratic governments in Bosnia and Macedonia, ultimately failed, because the army - which was supposed to be his greatest ally - sided with Milošević and Serb nationalists. Frustrated and politically impotent, Marković told his cabinet in September 1991 what he had gleaned from a wiretap that had come into his possession:
The line has been clearly established [between the Serbian government, the army and Serb politicians in Bosnia]. I know because I heard Milošević give the order to Karadžić to get in contact with General Uzelac and to order, following the decisions of the meeting of the military hierarchy, that arms should be distributed and that the TO of Krajina and Bosnia be armed and utilised in the realisation of the RAM plan.
In 1991, the U.S. cut off all financial aid to Yugoslavia until all 6 republics held free elections (1991 Foreign Operations Appropriations Law 101-513), contributing to another destabilization of the economy, along with the already big foreign debt of the country.
Marković remained in office even after the start of the war, only to resign in December 1991, isolated and without any authority.
Marković instead dedicated himself to a business career. In the early 2000s he worked as an economic advisor to the Macedonian government.
He appeared as a witness at Milošević's trial at the ICTY in 2003. This appearance broke his 12 years of silence; after that testimony, he gave an interview to the Zagreb-based Globus news magazine. In his testimony he stated that both Milošević and Tuđman confirmed to him that in March 1991 in Karađorđevo they made an agreement to get him out of politics.