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Trump's ego. He tweeted that he was sending missiles before checking with his commanders. To save face, he had to send in some missiles.

Long-term value of this attack is dubious. Announced with enough forewarning that Russians and Syrians moved all military assets before the strike.

Russians left all anti-missile measures disable during attack. They don't want US to know hoe bad, or how good, their anti-missile technology is.

You could be spot on and/or there was much more going on then we know. Trump is in a war with the deep state. There are definitely bad actors in Syria beholden to the deep state. Were they targeted and exposed?