The Articles of Confederation created a confederation in the United States. A confederation is a government in which the state government, not national, have dominant power. The leaders of the new nation feared that a strong, centralized government would lead to tyrannical monarchy like the British government.
This is not a violation of the Separation of Powers because he is influencing, not taking any action in the House or the Senate. If he was violating the Separation of Powers, that is not okay.
