The Armenian Revolutionary Federation (Dashnaktsutyun) has expelled one of its longtime leaders, Aghvan Vartanian, from its ranks because of his refusal to back opposition leader Nikol Pashinian’s bid to become prime minister.

Dashnaktsutyun voiced support for Pashinian’s opposition movement after pulling out of Armenia’s governing coalition following the April 23 resignation of Prime Minister Serzh Sarkisian. Accordingly, it decided that the seven members of the Armenian parliament affiliated with must vote for Pashinian’s becoming the country’s new premier at a May 1 session of the National Assembly.

During that session, Vartanian unexpectedly announced that he will not vote for the outspoken oppositionist who has led massive anti-government protests that have rocked Armenia. While acknowledging the sincerity of Pashinian’s pro-democracy agenda, he said that the protests could be exploited by unspecified foreign powers and result in “irreversible bitter consequences” for the country. He did not elaborate.

Dashnaktsutyun’s governing body in Armenia was quick to accuse Vartanian of violating the century-old party’s strict internal discipline and demand his resignation from the parliament. Vartanian tendered his resignation on Thursday. He will be replaced by another Dashnaktsutyun member.

The Dashnaktsutyun leadership announced on Friday that it has discussed the “disciplinary issue” and decided to also expel Vartanian from the party.

A former newspaper editor, Vartanian has been one of Dashnaktsutyun’s most prominent figures since 1990. The 59-year-old has held various leadership positions in the pan-Armenian party. He served as Armenia’s minister for labor and social affairs from 2003-2008.