The NIE vs VDH
Here's WaPo's assessment of the NIE's view of what caused the Iranians to go slow:
Intelligence officials credited increased international scrutiny of Iran's nuclear program and the threat of exposure of its previously undisclosed uranium enrichment efforts with influencing Tehran's decision to halt its nuclear weapons effort.
Senior intelligence officials said it is possible that Libya's decision to halt its nuclear program and the war in Iraq were also factors, but said there was no direct evidence of either.
Think of this as the CIA's professionals refighting the Iraq war against the vice-president - and winning this time.