Re: no further evidence
First of all, the Pentagon says the additional deployments were planned anyway. I guess you can choose to believe that or not as you wish.
Second, you are misinterpreting the situation. You make it sound like all of a sudden the Administration thinks we need more troops that we didn't need before. The 4th and others were already parked off Turkey, and were supposed to be halfway to Baghdad by now in full force with their own armor. If there was a miscalculation, it was not underdeployment, but betting the whole northern front on Turkey deciding to let us through. Now we have to haul everything back through Suez and south to where they can be deployed.