The guided-missile destroyer USS Porter launches a Tomahawk land attack missile aimed at Shayrat air base in Syria on April 6. (Mass Communication Specialist 3rd Class Ford Williams / U.S. Navy via AP)

In 1997, HarperCollins published “Dereliction of Duty,” a book by a major in the United States Army named H.R. McMaster. Veterans of the Gulf War knew McMaster for his heroism in defeating Iraqi armored forces in what became known as the “Battle of 73 Easting.” Students at the U.S. Military Academy at West Point knew him as a history teacher par excellence. However, it was McMaster’s 1997 book, a reworking of his 1992 doctorate thesis, that put him on the map.

“Dereliction of Duty” eviscerated the Joint Chiefs of Staff (JCS) and that organization’s poor working relationship with the civilian leadership of both the Kennedy and Johnson administrations. In particular, McMaster lamented the loss of direct access by the JCS to the president during the Kennedy/Johnson years, and the resulting abdication of decision-making influence to the secretary of defense and individual military advisers who would tell the president what he wanted to hear.

In the intervening 20 years, McMaster’s reputation as a scholar-warrior has, if anything, grown. A successful combat tour in Iraq as a regimental commander was seen by many as a model for others to emulate, and provided McMaster with entry into the inner circle of Gen. David Petraeus at a time when Petraeus was rewriting the U.S. military’s counterinsurgency doctrine that would guide America’s wars in Afghanistan and Iraq. McMaster played a major role in the revision of the relevant field manuals and, later, as director of concept and development learning, helped shape the Army’s overall doctrinal thinking for decades to come. Following the firing of President Trump’s first choice for national security adviser, Mike Flynn, Trump selected McMaster, by this time a lieutenant general, to be Flynn’s replacement.

On paper, the erudite McMaster seemed like an ideal choice, especially in the wake of the obviously unqualified Flynn. But there were whispers of concern about the nature of McMaster’s relationship with the president. Trump seemed overly enamored with McMaster’s reputation. This infatuation, combined with the hero-worship reverence Trump showed retired Marine Corps Gen. James “Mad Dog” Mattis, set the scene for history to repeat itself: An insecure president—possessing an inherently low opinion of the military (“I know more about ISIS than the generals do, believe me,” Trump famously quipped), and unwilling to hear divergent opinions on issues he had already made up his mind on—was now turning to a small group of military insiders who seemed inclined to tell him what he wanted to hear, as opposed to what he needed to know. McMaster, who literally wrote the book on this kind of failure of leadership, was now poised to commit the same dereliction of duty for which he once pilloried his predecessors.

During the night of April 6, Trump ordered a pair of U.S. Navy destroyers operating in the eastern Mediterranean Sea to launch 59 Tomahawk cruise missiles against targets located in and around the Syrian air base of Shayrat. The cruise missile attack was in response to allegations of a chemical weapons attack by a Syrian SU-22 fighter bomber operating out of Shayrat airfield on the morning of April 4 against targets in the town of Khan Shaykhun. The Syrian attack reportedly killed more than 100 people, including many children.

Images and video of dead and dying victims quickly made their way, via Syrian anti-government media activists including the well-known “White Helmets” rescue organization, to Western media outlets, where they were featured in breaking news stories over the course of the next two days. The activists claimed the victims had been exposed to a chemical agent released by weapons dropped by the Syrian aircraft. Initial assessments based on analysis of the images provided by the activists, together with statements made by people who claimed to have witnessed the events in question, indicated that the chemical nerve agent used was sarin.

Medical personnel, both those working in support of anti-regime rebels in Idlib province, where Khan Shaykhun is located, and in Turkey, where scores of victims were evacuated for treatment, likewise stated that the symptoms exhibited were consistent with exposure to an organophosphate chemical such as sarin. Blood samples—which could more specifically identify the chemical the Khan Shaykhun victims were exposed to—were drawn from victims by both the rebels and Turkish medical authorities and turned over to international investigators. Similarly, soil samples collected by rebels at the scene of the attack were turned over to international authorities. The lack of a defined evidentiary chain of custody for these samples, however, all but negates their utility toward any definitive resolution of what happened at Khan Shaykhun.

The Syrian government, together with its Russian allies, denied using chemical weapons against Khan Shaykhun, stating that the Syrian armed forces did not possess such weapons. The Russian defense ministry went further, stating that the Syrian Air Force had bombed what it thought was a rebel ammunition and weapons depot and that chemical agents stored in this depot leaked out, causing the casualties. The rebels deny the existence of any such depot, let alone a cache of chemical weapons.

The U.S. and its European allies have universally dismissed the Russian claim. While Russia and the Syrian government have provided evidence of both the possession and manufacture of chemical agents by anti-government rebels, including sarin nerve agent, the Russian counterclaim is virtually impossible to verify, especially since the site is under exclusive rebel control, and no independent investigators have been granted access to the area.

The Trump administration has unabashedly endorsed the rebel claims of Syrian government responsibility.

“It is in the vital national security interest of the United States,” Trump said in a statement following the April 6 cruise missile strike, “to prevent and deter the spread and use of deadly chemical weapons. There can be no dispute that Syria used banned chemical weapons, violated its obligations under the Chemical Weapons Convention (CWC) and ignored the urging of the U.N. Security Council.”

The president was even more specific about the weapon used—a “deadly nerve agent” that “choked out the lives of helpless men, women and children.”

Trump’s statement was striking, because it enshrined as fact that the government of Syrian President Bashar Assad violated its international obligations regarding the possession and use of a “deadly nerve agent”—sarin. Trump’s statement also carved in stone the proposition that preventing this kind of activity was a “vital national security interest” worthy of war.

This certainty drove the president to authorize an act of war, where the United States undertook armed aggression against a sovereign state. A key question that has emerged in the aftermath of the missile attack is whether the president complied with U.S. and international law in ordering it.

The Founding Fathers granted Congress the exclusive power to declare war through Article I, Section 8, Clause 11 of the U.S. Constitution. The president, whom Congress named commander in chief of the armed forces in Article II, Section 2, has the exclusive power to direct the military following any declaration of war by Congress. Moreover, the Supremacy Clause (Article IV, Section 2) declares that treaties made under the authority of the Constitution are an integral part of the supreme law of the land to which all Americans are subject.

While the above seems pretty straightforward, in reality the issue of war powers as they are applied to both U.S. constitutional and international law becomes pretty muddy, pretty fast. First and foremost, Congress, through the passage of the War Powers Resolution of 1973, ostensibly sought to codify this constitutional language by limiting a president’s ability to take the nation to war to cases where Congress had declared war, or through other statutory authorization, or in case of a national emergency created by an attack on the United States, its territories, possessions or armed forces.

Congress, however, through the specific language of the resolution, actually abdicates its role in authorizing war. The president has virtually unlimited powers to commit America’s military into combat for periods of up to 90 days, so long as he sends a notification to Congress within 48 hours of any such decision being implemented. Trump complied with this requirement, through a letter to the speaker of the House and the president pro tempore of the Senate, on April 8. He declared that he directed the attack “pursuant to my constitutional authority to conduct foreign relations and as Commander in Chief and Chief Executive.” He put Congress on notice that “[t]he United States will take additional action, as necessary and appropriate, to further its important national interests.”

While Trump contended his letter was in conformity with the War Powers Resolution (Public Law 93-148), some members of Congress countered that, while the president did well to inform Congress of the attack within the 48-hour window required by law, he would need an “Authorization for Use of Military Force” if, as Trump noted in his letter, he was planning on any “additional action.” The political reality, however, is such that once American forces are placed in harm’s way, it is difficult to imagine a scenario where Congress would do anything other than provide the president with the statutory authority required to wage war for the duration of the conflict in question. Nitpicking aside, the president appears to have acted within the intent, and most probably the letter, of the law.