I suppose you overlook the powers invested in the Office of President perhaps.
Don't fret over Tweets.....look at Executive Orders when issued.
Powers of the Presidency are not absolute but they are codified in law.
As a result, some are subject to challenge in Federal Courts to include right up to the Supreme Court.
Don't let TDS trip you up in thinking what the real situation is re the Powers of the Office.
You may not like him, you may hate his policies, but he is the President.