How does the Constitution support the president’s exercise of executive privilege?

Under the Constitution, the president is the head of the military, so he or she can do whatever is thought to be right.
The first president was George Washington, who was the first executive, so all presidents since then have been executives, too.
It outlines U.S. checks and balances, which allow the president to hold back information and the courts and legislature to push back.
The first president refused to show secret papers to Congress and was allowed to keep them secret.