The New York City Bar Association has sent an open letter to President Donald Trump on Tuesday seeking to call his “urgent attention” to various legal restrictions on his power to start a war with North Korea.

“[I] call your urgent attention to the requirements of the U.S. Constitution, federal legislation and international law … and, in particular, to the strict limits our constitution and laws impose on the power of our president to unilaterally commit the nation to war,” Bar Association President John Kiernan wrote. Kiernan noted that the letter was being sent to the White House on behalf of the Bar Association’s 25,000 members, who hail from nearly every U.S. state.