Who is most responsible for the structure of u. s. branches of government?

There is not one role that is more resonsible that the others they are equally important.The United States has three branches of government: the executive, the legislative and the judicial. Each of these branches has a distinct and essential role in the function of the government, and they were established in Articles 1 (legislative), 2 (executive) and 3 (judicial) of the U.S.Constitution.