It seems to be déjà vu all over again for Secretary of Defense James Mattis and the Joint Chiefs of Staff as they are once again fine-tuning military options for President Donald Trump as he determines what type of military action he wants to conduct against Bashar al-Assad’s Syrian government, which allegedly launched another chlorine attack against its people this past Sunday. The brazen attack, which claimed at least 70 victims, including numerous children, is just the latest atrocity conducted by the Assad government.

It was only a year ago that Trump ordered a Tomahawk missile strike on April 6, 2017, at the Al Shayrat airfield in retaliation over Assad’s chemical attack against his own people at the town of Khan Shaykhun — an attack that killed more than 80 people.

Following that U.S. aerial attack, President Trump said, “It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons.” Sadly, the U.S. attack did nothing to deter Assad’s blood-thirst, and now Trump finds himself in the same position that he was in last year.

Unfortunately for the commander-in-chief, the geopolitical situation this year is arguably much more complicated. Both the Russian and Iranian governments asserted that the international community’s calls for action against Assad were unwarranted, and both nations have been vociferous in their defense of the embattled Syrian regime.

Meanwhile, CNS News reports, “Syria’s Assad regime is set to assume the chair of a United Nations forum whose agenda includes an end to weapons of mass destruction, at a time when it is accused of using them against civilians in Syria.” Only at the UN…

Complicating the delicate situation even more is that on Monday, Israel appeared to launch a predawn airstrike against Iranian-backed militias at a Syrian air base, thus ratcheting up the tensions between these two Middle Eastern powers. It’s an open secret that Iran and Israel are engaged in kinetic operations against one another in Syria and are actively looking for opportunities to take the fight to one another.

It is against this tenuous strategic backdrop that Trump and his national security team are having to make some tough decisions about U.S. foreign policy toward Syria and the region as a whole. That is why Trump’s pronouncement last week that the United States will soon pull all 2,000 troops out of Syria is such a potentially damaging move for our nation and our allies in the Levant.

A look at the facts shows that the United States’ current fight against the Islamic State in Syria is not complete, notwithstanding the success of that same fight in Iraq. Recent reporting shows that one last ISIS stronghold in eastern Syria is on the verge of collapse and that the military mission of training Syrian Democratic Forces (SDF) is going well. Any move to pull resources at this critical juncture has the potential to eliminate gains that have been made over the last year.

More importantly, a precipitous exit sends a message to Iran that the United States isn’t dedicated to fulfilling its foreign policy goals, either in the short term or the long. Iran continues to pour a massive amount of personnel and munitions into Syria, as Tehran views the fight as an ongoing campaign to not only prop up the beleaguered Assad government but spread Iranian influence. The mullahs are hoping that Trump does pull troops out as it enables them to spread their tentacles of influence even more. That is why the U.S. can’t cede the region to Iranian proxies.

As national security expert Matthew RJ Brodsky writes, “Maintaining a military presence in Syria provides the U.S. opportunities to prevent the peaceful imposition of an Iranian post-war order on the country, and to disrupt Iran's logistical lines, including the land corridors it uses for moving arms and personnel.”

Barack Obama made a massive error in judgement when he pulled troops out of Iraq in 2011. It not only created the space for ISIS to metastasize throughout the area, it allowed Iran to strengthen its influence in the country as well. Obama’s team also promised to rid Syria of chemical weapons, and then crowed — repeatedly — about its supposed success. Look where we are now.

President Trump should learn from that mistake and pledge to keep a small footprint of troops and resources in Syria until the fighting is done and post-conflict transition is complete. A failure to do this will only embolden Assad to conduct more chemical attacks on his people and allow more innocent people to die.