The commons vote against the government was a big surprise. The proposal had already been watered down to make it more acceptable to MP`s, but the majority clearly believed that even this, had it been approved, could have been enough for the PM to have declared a mandate in favour of action.
The message here is that outrage is not a strategy, and the lack of a defined objective behind military action is the weakness.
This does weaken Cameron, and it is difficult to see how this can be positive for £. However, this is such a specific topic, that it is hard to see a vote of confidence being called by the Labour Party at this stage – and that is what would be needed for any real political upheaval.