However the President's discrimination against Muslims in Chad brought him to become a member of the rebel insurgent group FROLINAT, formed in 1966 to oppose the rule of Tombalbaye.
After the death of the organization's first secretary-general in 1968, a vicious battle for leadership ensued, which terminated with the victory of Siddick in 1969, even though he was perceived as an Anti-Arab and suspected of being a moderate leftist and not having any revolutionary apprenticeship.
What nominal control was left over the troops on the ground completely vanished in 1976, when almost all his cadres rebelled against his authority and accused him of never listening to his lieutenants and of never going himself to the field of operations.
In this meeting, the resolution of Hissène Habré and Goukouni Oueddei to not let those not present at Kano I to enter in the new government failed, as Sidick, Dana, and Acyl were accused by both of not having any troops on the ground.
Shortly after this, Siddick broke with the GUNT and fled in exile to Sudan, ceasing to play any part in the civil war.