Rick Moran has the sensible reason for the NIE report to be regarded as merely an advisory:
[T]he Administration is going for a third round of sanctions. The reason is exactly the same regardless of whether the Iranians have an active weapons program or not; they continue to defy the UN by expanding their enrichment program. Until Iran cooperates fully and the IAEA gives them a clean bill of health (while ensuring compliance through inspections and monitoring), sanctions should continue and be expanded the longer the Iranians refuse. The conclusions drawn by the NIE do not change this situation one iota. It is the enrichment program that poses a danger to the world and must be shut down until there are adequate safeguards in place that the Iranians will not use their knowledge to build a weapon.
Also, the Iranians could use the enriched uranium for weapons as well as power generation.
And before the Harry Reid "we've lost the war" crowd exults too much about the NIE, they should recall how they themselves have been sceptical of US intelligence in the recent past. You can't have it both ways.
Of course, the chorus of weasels and America-Last types will nonetheless use this as ammunition against President Bush, who in today's press conference had a deer-in-the-headlights inability to respond vigorously to thinly-disguised contempt in the questions that came his way. He seems to be more interested in placating a hostile media than vigorously defending his case. Or else, he simply can't vocalize adeptly and think on his feet as Bill Clinton used to do, even when Bill was fibbing right and left.
I always get the feeling that with GWB it's as if the head cheerleader had been promoted to quarterback. But GWB is no Tom Brady.