The Arlea Committee was (and as the High Moot today, still is) the real power in the Imperium. Any decisions they make are “suggested” to members of the Moot to raise in session. All decisions made by the Committee are passed.
In the early days of the Third Imperium, when the new Emperor Cleon I first ascended the Iridium Throne, he appointed the great families who had been signatories of the Charter of Arlea to form the High Moot. Though not widely publicized (and in fact many citizens of the Imperium, and even members of the Moot, had never heard of it), the highest level of decision-making within the Moot was the Arlea Committee, which in the year 0 comprised the heads of the original nine great houses which had signed the Charter of Arlea (including the head of the Zhunastu house, Emperor Cleon I).