Complex sentence: Mitchell argued that a single chamber of Congress was constitutionally incompetent to take actions not expressly permitted by the constitution, stating it proscribes either chamber from unilateral action except in matters of parliamentary procedure.
Split into simpler sentences: Mitchell argued that a single chamber of Congress was constitutionally incompetent to take actions not expressly permitted by the constitution. In Mitchell's view, the principles of bicamercalism proscribed either chamber from unilateral action except in some limited matters, such as questions of parliamentary procedure.