Why did America back down on Iran?

the National Intelligence Council released a mild report on Iran's intentions to get the bomb.
Stating that Iran gave up its nuclear program back in 2003
Why this sudden U-turn? Why would the Bush administration let out a report that contradicts all there hard work they've been doing to push sanctions on Iran?

Recently at the Annapolis conference which was held to boost peace talks between Israel and the Palestinians, Prime Minister Olmert met with Bush on several occasions to discuss Iran. A week later America releases a National Intelligence Estimate (coordinated judgments of the US Intelligence Community made up of 16 intelligence agencies) on Iran. Then Israeli Defence Minister Ehud Barak publicly challenged the US intelligence consensus that Iran had stopped its nuclear weapons programme. Why would you give your enemy leverage?

Are the Americans trying to relieve themselves of the duty to face this problem head on, are they leaving the burden on Israel? Is this all a intricate ploy to give the Iranians some breathing space so that they can be caught off guard or maybe even open a channel of communication on a lower level of trust?

The fact remains, Iran is a threat! Whatever is going on here, I sure hope something is done soon before mad men like Ahmadinejad get even madder