Georgetown law professor Martin Lederman (a former executive branch lawyer and a top authority on war powers) pointed out three weeks ago that an unapproved attack on North Korea would violate not only the U.S. Constitution but also U.S. law as set forth in a binding treaty and the fundamental charter of international law.

Begin with the Constitution. The framers and ratifiers rejected the British King’s “prerogative” to go to war (as recently as 2004, a Parliamentary report indicated that the government of Britain still has the power take the nation into war without parliamentary assent). At the Constitutional Convention, James Madison and Elbridge Gerry proposed language granting Congress the power to “declare war,” leaving, they said, “to the Executive the power to repel sudden attacks.”

Since the dawn of the Republic, presidents have been crowding the line between their command authority and Congress’s control of the military. Jefferson sent the Navy to fight the Barbary pirates, thus signaling that the new nation would defend itself on the seas. A century later, Theodore Roosevelt sent a naval squadron against the last Barbary pirate, Mulai Ahmed er Raisuni, in a show of force conveniently timed to highlight TR’s renomination.

Sometimes presidents sought approval beforehand, sometimes afterwards, and sometimes they ignored or defied Congress. In 1917, Woodrow Wilson sought authority to arm American merchant ships against German raiders (the U.S. was still at peace). A Senate filibuster killed the bill; Wilson armed the ships anyway.

By 1950, President Harry Truman felt empowered to commit the U.S. to full-scale “police action” in Korea without authorization; leaders of both parties acquiesced. Presidents Lyndon Johnson and Richard Nixon expanded the war in Southeast Asia and presidents expanded war-making authority by committing the U.S. to war in Southeast Asia while concealing the decision from the public. Congress responded with the War Powers Resolution of 1973, limiting presidential authority to commit U.S. forces into actual or imminent “hostilities.”

Presidents have pushed against the WPR as well. George W. Bush’s lawyers asserted that the power to initiate armed conflict was a decision solely entrusted to the president, and that Congress had no role to play. Nonetheless, when he took the nation to war in Iraq, Bush got authorization. When Obama authorized air strikes in Libya, his lawyers argued the raids were not “hostilities.”

Congress and the public scorned Obama when he actually asked for permission to intervene in Syria. This, perhaps, is the true lesson of the drift toward executive power over war and peace: Congress doesn’t really want its war power back.

Since becoming President, Donald Trump has threatened the President of Mexico with American troops; he has startled the Pentagon by announcing that he has a “military option” for Venezuela. Pushing past Obama’s scruples, Trump intervened in Syria on April 6; he has never bothered to explain to the nation or to Congress why, or what the nation’s objectives are.