My second preliminary point relates to the appropriate action of the United States and the international community. The South African case is neat proof of the fact that even a nation under international embargo can build both functional nuclear weapons and medium-range ballistic missiles. Given what appears to be our very limited knowledge of the extent of the Iranian nuclear weapons program, as well as the fact that human, not physical, capital is the key axis on which their chances turn, effective preventative action is practically impossible. Any debate will deal only with whether or not the United States should inflict punitive damages, which don't, at first glance, appear to me to be worth the trouble.
Anyway, onward to the discussion.
Let me first address the problem your demand that I take Iran's word for it.
Even if one does not accept the conclusions of a 2007 NIE that reported that Iran had been pursuing a nuclear weapon until 2003, the Iranians were indisputably enriching uranium in secret for some eighteen years. The extent of Iran's progress during the period just mentioned is as yet unknown. Tehran resisted full disclosure and impeded IAEA investigations. As a consequence, the United Nations Security Council ordered Iran's uranium enrichment halted in December 2006. Failure to comply sparked three rounds of international sanctions. As of 22 September 2008, the IAEA stated that it would be unable to certify that Iranian nuclear activities were entirely peaceful without additional cooperation. Iran has prohibited IAEA access to subterranean facilities, and now subscribed to the minimum timeline for prior notification of new nuclear facilities. On 22 May 2009, an article published on the BBC website, titled "Q&A: Iran and the nuclear issue," confirmed that Iran was still "not cooperating with its request for an answer to questions about possible studies on nuclear warheads carried out in the past."
Certainly, Iran has not behaved as a "model" international citizen. Why do you propose we give the benefit of the doubt to an entity that has resisted transparency? If Iran is indeed pursuing a civilian nuclear fuel cycle, what reason can they have to avoid compliance?
The South African example also suggests why we should be wary about regarding the 2007 NIE as evidence that Iran's bomb-making days are over. Remember the old adage about leaving the kitchen when the heat becomes too great? Iran may very well have completed the complex technical processes associated with preparing a nuclear warhead. With this knowledge in hand, the country could afford to step back from the brink - just as South Africa did after it was "found out" by the West immediately prior to a test.
Now, to address your complaint that this is all the fantasy of the "right-wing." The 2007 NIE in fact caught many off-guard. It contradicts a decisive statement from the French Foreign Ministry in February 2006, reported by Molly Moore in the Washington Post, that a civilian nuclear program is absolutely inconsistent with Iranian activities. (Molly Moore, "Iran Working On Nuclear Arms Plan, France Says: Official Rejects Claim About Civilian Program," 17 February 2006, p. A13
The BBC meanwhile reports that, "[O]n March 2008, a senior British diplomat said: 'Many of us were surprised by how emphatic the writers [of the NIE] were... I haven't seen any intelligence that gives me even medium confidence that these programs haven't resumed.'" ("Q&A: Iran and the nuclear issue," BBC News [Online], 22 May 2009)
Still more recently, in September 2008, the European Union stated that it believed Iran was still pursuing an atom bomb, and might be "close" to arming missiles. (Lisa Bryant, “EU Says Iran Close to Developing Nuclear Weapon,” Voice of America News Online, 24 September 2008)
In October 2008, Newsweek reported on the embarrassing fate of an Iranian-Canadian informant, titled "Sinbad," who had provided the BND "high-quality Iranian government documents" over the course of some ten years - including information said to relate to "nuclear delivery systems." (Mark Hosenball, "Nukes: Too Deep to Hit," Newsweek, 25 October 2008)
The ability to lob conventional high-explosive warheads is not particularly useful. Ergo, I find it highly unlikely that Iran intends to stop at arming those missiles with conventional warheads.The idea that you don't need silos unless you're pursuing nukes is just bullshit - you can deploy conventional missiles in silos, just like you can deploy nuclear missiles on TELs, and this is apparently what Iran is doing.