A frequent source of pundit error is the "that was the plan" fallacy. To the extent that political leaders actually make plans (But see, Boehner, John) they rarely come to fruition, especially plans that require two or three steps of execution.
After step one, events intervene and everyone re-plans their next two moves. Wash, Rinse, Repeat.
So: Syria? Every analysis of Obama's action seems to assume that he had a concrete belief that Congress would quickly approve air strikes. Thus, he must have "miscalculated". Moreover, anything that happened during the delay--ie, diplomatic success--is either A. a happy accident or B. a victory for Putin at Obama's expense.
But why would Obama have believed such a thing? Public opinion was dead-set against strikes and Congress was in a "District Work Period," i.e., members were at home, meeting with constituents who were (as already noted) strongly opposed.
Obama's moves are best understood as those of a generally risk averse leader facing two unknowable unknowns: the outcome of air strikes and the position of Congress.
Good knowledge of one or the other would have dictated one approach or another. If he knew for sure that he had the backing of Congress, he could make the strikes, confident that the responsibility for unforeseen bad consequences would be shared. Or if he knew the strikes would start a chain reaction of success in Syria, he would act without approval and maximize his credit.
But, knowing neither, he wisely combined the unknowns in a kind of two-negatives-make-a-positive maneuver. If Congress voted no, the strikes do not happen, and all the future bad in Syria could be blamed on Congress. Or they vote yes, strikes do happen and, if Syria goes from bad to worse, Obama would not face all the blame.
The thing that made this strategy irresistible was the current state of the GOP. Forcing them to make a policy decision with life or death consequences would shine a spotlight on their total inability to think seriously about anything. That was not unknown. It was a sure thing.