This is the beginning of a piece by Tony Blair that Guido linked to a few days ago. The rest of it is behind the Times paywall. But I think the basic folly that MPs were voting against, and which Blair presumably goes on to enthuse about, is actually quite well described:
The announcement of the summit in Jordan this week, after the use of chemical weapons in Syria, is very welcome. Western policy is at a crossroads: commentary or action; shaping events or reacting to them. After the long and painful campaigns in Iraq and Afghanistan, I understand every impulse to stay clear of the turmoil, to watch but not to intervene, to ratchet up language but not to engage in the hard, even harsh business of changing reality on the ground. But we have collectively to understand the consequences of wringing our hands instead of putting them to work.
But what is now collectively understood is that the consequence of this determination to be for ever “shaping events” and “changing reality on the ground” in the Muslim world only seems to be futile wars which expend much treasure and blood but accomplish very little. That, I think, is what MPs were voting against, egged on by just about all their voters. Where, ask the voters, is the British national interest in all this proposed action? What on earth is so wrong with reacting to events?
However, Blair’s claim that the choice is between ratcheting up language and taking action is surely wrong. The idea of all the verbal ratcheting of recent days has been to hustle MPs into voting for action. If the idea of action is now set aside, the verbals will be dialled down again.