President Trump is coming close to his self-imposed deadline to make a decision on how the United States will respond to the latest suspected chemical weapons attack by the Assad regime in the Syrian town of Douma. While the administration is still considering various options, everybody is anticipating that the order to strike the Syrian government has largely been made. Israeli Prime Minister Benjamin Netanyahu has told his security ministers that “there is a high probability” of U.S. military action in Syria, and Senate Foreign Relations Committee Chairman Bob Corker, R-Tenn., speculates that the White House will in fact respond forcefully.

Syrian President Bashar Assad appears to think so too; the Syrian military has reportedly issued an alert to all of its bases, a preparation to muster its defenses.

For the second time in just more than a year, Washington is on a war footing in Syria, with many lawmakers urging Trump to use force. But in the meantime, we should not lose sight of the bigger picture.

1. In the event Trump orders a missile attack against Assad regime targets, it would be an unlawful and unconstitutional use of military force. The president of the United States is not a monarch, and the United States of America is not a monarchy. Although Trump is granted commander in chief powers, he cannot direct the U.S. military to engage in kinetic action unless one of three conditions are met: the U.S. has been attacked or is under attack; Congress has declared war; or Congress has passed an authorization for the use of military force. A unilateral decision by Trump to strike the Assad regime would fail to meet any of those requirements and would thus be deemed unlawful. If the administration believes it has a case for action, it needs to present it to the legislative branch and let America’s elected representatives make the decision.

2. Retaliating against Damascus for using chemical weapons will not change the nature of the war or do anything to assist a muddled, if not nonexistent, diplomatic process. It will have little (if any) impact on Assad’s ability to wage a war against its opponents (a war that Assad views as an existential struggle for himself and his family) and may not even be successful in serving as a deterrent to stop further chemical weapons attacks from happening in the future. As the April 2017 missile attack on the al-Shayrat air base demonstrated quite poignantly, punitive strikes have had a minimal effect on Assad’s internal calculations. Dozens of chlorine gas attacks have occurred in the 12 months since that operation was conducted, hardly a great example of deterrence theory. Unless Trump is willing to use a greater amount of force against a much larger target set - throwing the U.S. into the middle of a civil war that it has no national security interest in being involved in - the Syrian government will adapt to the situation as it has throughout the war.

3. As much as commentators in the Washington bubble would like to argue otherwise, there is a likelihood that Russia will respond to an American missile attack. To bet on the Russians not responding in some way is to bet on the best case scenario, the type of lousy contingency planning that has gotten U.S. policymakers into severe trouble. Retaliation from Moscow will increase immeasurably if Russian soldiers are killed in the course of the operation - not an unlikely development given the Russian military’s proximity to Syrian personnel. And if Moscow does indeed retaliate against the American destroyers or aircraft that launched the missiles, one can clearly imagine a slippery slope to a national security crisis with a nuclear-armed power. Is the cost of getting into a fight with the Russians worth the benefit of sending a message that Assad may choose to ignore?

Former Defense Secretary Donald Rumsfeld was famous for talking about “known unknowns.” There are some things the U.S. will never know. But in the case of a U.S. military strike against the Syrian government, we will know that the operation will be unauthorized, ineffective, and unnecessarily dangerous.

Daniel DePetris (@DanDePetris) is a contributor to the Washington Examiner's Beltway Confidential blog. He is a fellow at Defense Priorities.