This is not my theory but a Mr. Salisbury who I have enjoyed on Twitter since @Guinness2 posted one of his threads during the original Omnibus Bill freakout.
Salisbury contends this 'attack' on Syria is a diversionary tactic to ultimately isolate and denuclearize Iran (remember Trump did mention Iran in tonight's announcement). How this denuclearization will be accomplished I cannot see right not but perhaps it will all be revealed soon.
Some quotes from Salisbury's tweets from this evening:
The folks in the White House are doing what needs to get done & they're not doing #DeepState bidding. Syria is a Deep State distraction. De-nuclearization of Iran is the goal & the mission.
Russia & Iran are heavily in bed together. This could very well be peeling Russian support away from Iran. You can be assured Putin has his own #DeepState #Cabal problems with his Iran alliance.
DeepState wanted attacks on Assad & Russians. What @POTUS attacked were Iranian Diplomats, ISIS funders, Muslim Brotherhood Offices & Syria Free Army Iran proxies. That's how you take lemons and make lemonade.
His Twitter page.
This could all be fantasy. But wouldn't it be just like Trump to appear to be appeasing the Deep State while taking out the true 'bad guys'?
EDIT: After I posted this I saw a WikiLeaks tweet where they wrote, "Full video: Pentagon briefing with US Secretary of Defence General Mattis on strikes against Syria. General Mattis claims approximately 100 strikes (double one year ago) limited to chemical weapons supply chain and that there will be no further strikes."
The volume does get raised after several seconds.
Edit 2: By attacking Iranian posts (if true), Russia is forced to either fight us on behalf of their friend (not likely) or hold back on making any counter-maneuvre. Iran would then be isolated without Russia 'having their back'. This could put Iran in the awkward position of being 'next' unless they dismantle their weapons.
If all that happened is we bombed some chemical-making facilities, what is the real harm? Apparently there was not one soul lost in this attack tonight.