32 U.S.C. § 110 — Regulations

This section gives the President power over the National Guard. The President "shall prescribe regulations, and issue orders" — meaning the President must create rules and give directions for the Guard. These rules must do three things: organize the National Guard, keep it disciplined, and govern how it operates. The section does not spell out what those regulations must say. It only requires that the President be the one who makes them.