Thankfully the containment side won the policy debate even as the political debate had its moments embracing the rhetoric of rollback. During this time the United States saw what it perceived to be a mortal enemy build a nuclear arsenal with thousands of deployable warheads, saw another strategic competitor/ally in China build a minimally credible strategic deterrant, and saw numerous secondary and tertiary powers either built a nuclear arsenal (Isreal, South Africa) or develop the capacity to do so.
Since the end of the Cold War, we have seen three more declared nuclear nations (Pakistan, India, North Korea), one of which is on the 'Axis of Evil' and another due to a massively complex internal situation is both aiding and opposing US interests in Afghanistan. We have survived both North Korea and Pakistan building (probable) working nuclear weapons, and we will continue to survive this basic fact. Does the possession of North Korean nuclear weapons change our option space? Yes, marginally so, as I believe that the US policy of containment and economic incentives would have been roughly the same no matter what.
Containment and management are legitimate options that have served the United States pretty damn well. It has kept the US out of starting full scale nuclear war in 1950 or 1954, or 1962 during the Cuban Missile Crisis; it has provided a reasonably workable MO in Pakistan right now, and a continuation of a strategically favorable status-quo on the Korean Pennisula. I say this because of some members of the Right's insistence that it is intolerable for Iran to continue within its NPT allowed activities:
Basically we are being left without much choice, unless you consider allowing Iran to have Nukes as an option. Diplomacy, predictably, is failing. So are sanctions. The moonbats will go mad, and it may be hard for America to swallow, but if we don’t do something before it is too late, we will regret it down the road.
Not 'rolling back' hostile regimes by military actions up to and including nuclear attacks has been a pretty damn good policy of the United States with a sixty year history of strategic success. If Iran is actually capable of developping nuclear weapons and actually has a government wide consensus that it is in their best interest to do so (which is up for debate), the constriction of option space is still several years at the very least down the road, and doing nothing is a viable policy alternative as the militaristic chest thumping right now is providing stronger incentives for everyone to engage in negative sum behavior.