NIE presents a major obstacle to those who are pushing for military confrontation. In many ways it is a severe blow to their agenda. However, I wouldn't go as far as to say that the risk has been significantly reduced or eliminated.
From the Israeli perspective, the fear is that if pressure is off of Iran, Israel would be left having to accept the balance of power in the region significantly shifting toward Iran. It's not an existential threat, but it would definitely be a problem for Israel.
I do believe that the very tense relationship between the United States and Iran presents a challenge to the United States. But to discuss Iran as that type of a threat I find somewhat unconvincing, mindful of the fact that Iran actually doesn't have those military capabilities that would be needed to refer to it as that type of threat.
Iran has, by virtue of its growth and by virtue of the United States' mistakes in Iraq, tilted the balance of power in the Middle East. That is the case, but that doesn't necessarily mean it is a threat.
The intelligence services would probably be in a better position to make an assessment of the advancement of the Iranian nuclear program than Podhoretz or Ledeen. They don't have access to any specific information. So for them to dismiss it has no great value because they have no authority whatsoever on this issue. For them to push forward with their efforts to get a war started between the U.S. and Iran, you certainly cannot say that Iran does not have a nuclear program. If you say that, then the justification for war has basically been eliminated.
There seems to be a consistency, in that people who have had access to the Iranian program - people who actually have had boots on the ground and have been able to investigate and inspect the program - have consistently been saying these things.
The United States has weakened itself with Iraq; Iranians feel victorious - they feel capable of filling the void. I think from the very outset the nuclear issue has been secondary to the more strategic outlook, in which the United States has, since 1991, pursued a policy that it cannot permit any country in the region to become too powerful and challenge American hegemony.
Beyond that is the fear that the United States will end up negotiating and agreeing to a deal with Iran. The Israelis do not like that either because they fear the deal will come at the expense of Israel's security interests. From an Israeli perspective, the NIE makes the risk of some sort of settlement much greater.
Unfortunately, every time the United States has tried to pursue a peace deal between the Israelis and the Palestinians by beating back Iran and trying to isolate Iran, it has failed. And it has failed under much better circumstances.