There he graduated from Faculty of Law of Paris and joined the Young Turks, establishing contact with important members of the Committee of Union and Progress (CUP) such as Ahmet Rıza, Mizancı Murat, and Dr. Nazım.

After the 1912 general election which the committee rigged in favor of itself, the opposition organized a group in the military known as the Savior Officers to shutter parliament.

In a session of parliament on 25 July, Halil read to the Chamber of Deputies a death threat from the group, announcing that he was going to continue his position in government.

He was appointed as President of Council of State in Said Halim Pasha's cabinet, and accompanied Talaat to Bulgaria to negotiate a peace treaty to end the Second Balkan War.

[5] A special parliamentary committee organized to investigate the causes of the Ottoman Empire joining WWI summoned Halil to questioning several times but nothing could be definitively proved.

He was finally arrested on 10 March 1919, and appeared before the Special Military Tribunal that was punishing CUP members and war profiteers.