You are correct that the current situation in Syria is almost entirely due to Obama’s weakness and indecision in 2013. As Commander in Chief he could have ordered the same kind of proportional response that Trump just did, sending the Assad regime a message that the use of nerve gas against civilians will not be tolerated. He chose to seek Congressional permission precisely because he knew they wouldn’t give it: that gave him a face-saving out from having to honour his word.
Trump has just proved two things:
- The President can order a military strike without Congressional approval, and
- This means the strike is a surprise, since it hasn’t been telegraphed to the enemy by being discussed in Congress, and that’s why Congressional approval is not required.
The current administration’s policy is to not get involved militarily in Syria, but gassing children over-rides policy, and demands a response. It got one.