In practice, however, the constitution became an oligarchy.

The Senate, not the Comitias, ruled Rome.

Moreover, the Senate was controlled by a class who claimed all the privileges of a nobility.

The Comitias were rarely called upon to decide a question.
Most matters were settled by a DECREE OF THE SENATE (_Senatus Consultum_).

To be sure the Comitia declared for war or peace, but the Senate conducted the war and settled the conditions of peace.