He helped to create the Second National Front in 1960 and, along with other pro-Mossadegh politicians, advocated a democratic system and a Shah that reigns but does not rule.

Because of this threat, the Shah tried to appoint Sadighi as the prime minister in order to rally the moderates behind the government and neutralize the religious opposition.

[1] However, the plan collapsed over Sadighi's insistence that the Shah remains in the country and that full executive powers be entrusted in the premier's cabinet, two things that the Shah refused to grant.

Because of this, Sadighi left the scene and the Shah instead appointed Shapour Bakhtiar (one of the other leaders of the National Front) as Prime Minister.

Sadighi was a patriot who never left Iran and lived in Tehran until his death in April 1991.