President Donald Trump initiated strikes on the Syrian military on Thursday, a bold and risky response to Syrian President Bashar Assad’s latest use of chemical weapons against his own people. In lengthy internal notes that were distributed to U.S. government agencies late Thursday evening, which I obtained in full, the administration lays out its justifications for the strikes and the challenge the United States is now laying at Russia’s feet.

The notes were meant to be used as responses to various questions from journalists and were cleared through the interagency process for use on background as a “U.S. official.” They begin by explaining that the United States has initiated a series of strikes involving 59 precision guided TLAM missiles against Shayrat Airfield in Syria, a site the administration says was associated with the Syrian regime’s chemical weapons program and directly linked to the attack Tuesday in Idlib.

“We assess with a high degree of confidence that the chemical weapons attack earlier this week was launched from this site by air assets under the command of the Assad regime,” the administration document states. “We also assess, with a similar degree of confidence, that the Assad regime used a chemical nerve agent consistent with sarin in these attacks. As you know, Damascus and Moscow assured us all these weapons had been removed and destroyed.”

The document calls Assad’s attacks on Syrian civilians in Idlib and Hama an “unconscionable atrocity” that has focused the world’s attention on the “ongoing carnage” in Syria as well as a “disturbing escalation” of use of chemical weapons against innocent civilians over several years.

In its initial talking points, the administration did not not explain what legal justification Trump is relying on for the use of force under U.S. law but referred to Syria’s repeated violations of international law. But late Thursday night, the White House legal office issued supplementary talking points to assert a more specific legal justification.

The administration is invoking Article 2 of the Constitution as its legal justification for the strikes, asserting that the president has the power to defend the U.S. national interest. In this case, the U.S. national interest is described as “promoting regional stability, which the use of chemical weapons threatens.”

The Trump administration is claiming this justification is similar to what the Obama administration used in 2011 to use force in Libya.

“No authorization from Congress is necessary,” the document states. “The U.S. strikes were a justified use of force because of several factors, including promoting regional stability, discouraging the use of chemical weapons, and protecting a civilian population from humanitarian atrocities.”

The administration also says Russia seeks to sow confusion in the global community about who is responsible for the use of chemical weapons against the Syrian people and rejects the Russian government’s claims that the recent attack was aimed at an opposition chemical weapons depot. “It is a completely implausible assertion, and demeaning of those innocents who lost their lives,” the notes read. “Russia promotes a set of false facts, supported only by the Assad regime and its backers, much like it did after the attack on a UN convoy in northern Aleppo last September, or after the horrific use of chemical weapons in Ghouta in 2013, and as it does after each and every atrocity launched by the regime.”

The document accuses the Russian government of reneging on the 2013 bargain it struck with the Obama administration following the chemical weapons attacks of that year. The United States is presenting Russia with a challenge, pressure Assad or admit its diplomatic impotence.

“Russia faces a choice: either it takes responsibility for ensuring that Assad complies with the removal of these weapons as Russia committed it would do or it admits that it lacks the ability to control Assad,” the document states. “Russia’s posture must change if the Syrian conflict is ever going to be resolved — and for the sake of our humanity, it must.”

The talking points also criticize the Iranian government for propping up and shielding Syria’s brutal dictator for years. Iranian forces, Shia militias, Hezbollah and other “allied Shia militant foot soldiers” have played a key role in the killing of hundreds of thousands of Syrians, the document states.

Overall, the Trump administration is arguing that the Assad regime’s brutality and its use of chemical weapons “presents a clear threat to regional stability and security as well as the national security interests of the United States [and] our allies.”

Assad’s actions have fueled the rise of terrorist groups such as the Islamic State and al-Qaida, displaced millions of Syrians and destabilized the region, the document states. It concludes: “Weapons of mass destruction use by any actor lowers the threshold for others that may seek to follow suit and threatens the international legal regime prohibiting the use of chemical weapons.”

These talking points go a long way to showing how the Trump administration is thinking about Syria and why it decided to initiate Thursday’s airstrikes, but it leaves several crucial questions unanswered. Chief among them is, what happens next?

(c) 2017, The Washington Post · Josh Rogin