As for his meeting with Putin on the sidelines.....Putin already stated he's 'not looking for permission from Obama' to do anything he might opt to do in Syria. All Obama can do is hope for a photo op so it looks like he's significant.
Even CNN is saying now that he let our alies down. That our alies need to hear that we would be on their side and work with them.
And that's really it in a nutshell, isn't it.