I suspect the motive of President Trump ordering missile strikes in Syria is because he is a serial liar. Until recently, he was most definite about not interfering in Syria. When asked by a Twitter user what he would do about the situation as president, he said, “I’d let them all fight with each other.”
Now, he bemoans the fate of “innocent children, innocent babies, babies, little babies.” I believe it is more than a coincidence that he ordered these strikes just when his popularity has reached a new low and the heat is being turned up on possible collusion between his administration and the Russian government.
He also wanted to deflect attention from the infighting among his coterie of advisers and the failure of his proposed healthcare legislation. I don’t know the cost of 59 Tomahawk missiles, but posit that it would buy lots of humanitarian aid for all of those innocent babies.