I'd suggest that it's far too early to judge how Obama's role will be judged. The way I indicated is the obvious way that his people will seek to spin it - and the crucial thing determining how far that takes is going to be what actually happens.

If the chemical weapons get eliminated, if there is a peace conference that leads to an end of the civil war, if a regime is established in Damascus which at least looks better - and if, as seems quite on the cards, there is a rapprochement with Iran...

We tend to read back into history without always appreciating how events were initially seen. Things we think of as masterstrokes by politicians were often seen at the time as catastrophic blunders. And vice versa.