The inimitable Victor Davis Hanson:
Are they now to suggest that Republicans have been warmongering over a nonexistent threat for partisan purposes? But to advance that belief is also to concede that, Iran, like Libya, likely came to a conjecture around (say early spring 2003?) that it was not wise for regimes to conceal WMD programs, given the unpredictable, but lethal American military reaction.
Since the lesson of 2003 seemed to be that the United States would strike states that it suspected to have WMD programs whether or not those programs actually existed, it's hard to credit this logic. Again, Libya gave up its weapons program as part of a long term opening to the West, and did so without any implicit or explicit threats from the United States or the United Kingdom. And of course, Davis can give no account of why Iran apparently learned from the Iraq example (where the U.S. attacked a state that did not have WMD), and not from the North Korea example (where the U.S. failed to attack a state even as it quite openly flaunted its development of nuclear weapons and ballistic missile technology). But then, this is a worldview in which expressions of strength never have any downside (even if, as with the invasion of Iraq, they actually reveal weakness), and our enemies are always incorrigible and unappeasable (except when they're not).
For some further reading, see Jeffrey Lewis, Dan Drezner, Kevin Drum, Yglesias, Plumer, and Eric Martin. Yglesias also has further commentary on 2003:
I think it's important to put the revelations that Iran halted its nuclear "program in 2003 primarily in response to international pressure" in the context of the broader trends in US-Iranian relations that Gareth Porter (among others) have reported on. Specifically, in 2003 we know that the Iranians attempted a diplomatic opening to the United States.
Right; it's critical to remember that Iran had a positive influence on U.S. efforts in Afghanistan in 2001 and 2002, and gave every indication that it was looking for diplomatic accommodation with the United States even before the invasion of Iraq.
-- Robert Farley