George Bush got authorization from Congress, but State Senator Barack Obama didn't think a strategy of preemptive strikes set a good precedent. President Obama seems willing to make full use of this precedent now. This must be some more of that Obama evolution thing.
Zoom to bout the 1:50 mark if you are in a hurry.
It is interesting how closely related the two decisions are. Iraq used chemical weapons against their own people. So, has Syria. WMD is the driving factor in both decisions.