Such a strike would amount to a punitive action against Syria for what the US and its allies consider blatant use of chemical weapons against civilian populations within the country, but they still carry the risk of sparking War with Russia.
Ryan Bohl, a Middle East analyst at Stratfor, a geopolitical consulting firm, told Business Insider that Syria's chemical weapons facilities lie under the umbrella of Russia's air defenses, but not actually close enough that a strike on the facilities would endanger Russian troops. Russia has threatened to use its air defenses against US missile strikes.
Russian officials have also threatened to counter-attack the US if missiles fly over Syria, potentially by attacking US Navy ships or submarines.
Dimitry Gorenburg, a senior research scientist at Harvard's Davis Center for Russia and Eurasian studies, told Business Insider that Russia had flown in aircraft that specialize in anti-submarine warfare to Syria. Russia has moved its warships out of a naval base in Syria after Trump announced that the strikes were coming in a move they chalked up to self defense.
Russia operates out of airfields in Syria, but it's unclear if the US will target those bases. Syria has moved most of its jets to bases with Russian protection in fear of the coming strike.
White House Press Secretary Sarah Huckabee Sanders said on Wednesday that the US wasn't afraid to target Russian assets in its strike on Syria, but a report from a Russian website says the US has been coordinating with Russia to avoid hitting its troops, and will provide a list of targets before a strike to avoid escalating warfare between the world's two greatest nuclear powers.
Russia's UN Ambassador Vassily Nebenzia urged the US on Thursday to avoid military action, saying the "immediate priority is to avert the danger of war."
Asked if he was referring to War between the US and Russia, Nebenzia said, "We cannot exclude any possibilities unfortunately because we saw messages that are coming from Washington. They were very bellicose."
"They know we are there, I wish there was dialect though the proper channels on this to avert any dangerous developments," he said. "The danger of escalation is higher than simply Syria because our military are there ... So the situation is very dangerous."
"Putin is not interested in a shooting War with the West," Gorenburg said. Due to the extreme risk of War escalating into a nuclear conflict between the world's two greatest nuclear powers, and the fact that "the Russian conventional forces just aren't as strong as the US forces," such a fight "would not be a good outcome for Russia."
So far, Trump has played coy about the timing of the strike, saying Thursday "we're looking very very seriously, very closely at that whole situation and we'll see what happens folks," and that the strike could happen "fairly soon."
Meanwhile France and the UK have been openly pondering participating in the strike and sending their own forces to the region.
The US, with or without allies, has enough military presence across the Middle East to crush Russian forces in Syria, but a direct attack on Russian forces will always carry the risk of escalating a conflict into nuclear war.