Curtis the Monarchist is correct, Congress is the ultimate power. They have not just the power of purse but the power to remove Presidents & judges at any time.
A Red 2/3 Senate & bare majority House could remove every federal judge - this was the intent of the Constitution.
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Let me sharpen this point.
The point is: if Trump, or you, or me, had absolute control of Congress, we would have absolute sovereignty.
Whether the Congressmen we have now are free agents, or lackeys of some higher power (corporations, Jews, UFOs, etc) is beside the point