Gerson describes Obama's approach: "The exact shape of a possible Iran deal remains unknown. I’m on record predicting that it may be a bad one — a very unlikely throw of the dice that a terror-sponsoring, clerical regime will become a minimally responsible regional power."
I contest the analogy. When one throws dice one risks somethign which would have been safe if one didn't throw the dice. I agree that, if there is an agreement, the world will be a risky place and one of the risks will be that Iran makes an atomic bomb. But, Gerson certainly doesn't describe a less risky approach.
His proposal is: "The alternative to a bad nuclear deal is not war; it is strong sanctions and covert actions to limit Iranian capacities until the regime falls (as it came close to doing in 2009) or demonstrates behavior change in a variety of areas. " This would be a throw of the dice. It is clearly a high risk strategy for two reasons. First, while tough sanctions and cover operations might work eventually, there is no reason to think they will work before Iran has the bomb; Gerson's approach gives Iran no incentive to stick to their current policy of not working on a bomb (as their policy is assessed by the US intelligence community). Second, pressure on Iran might cause the current regime to fall, but it doesn't mean the replacement will be preferable.
I also note the dishonesty in the first sentence I quoted. Note that Gerson doesn't consider a good nuclear deal a possible alternative to a bad nuclear deal. His proposed strategy has nothing to do with the details of a nuclear agreement. the "may be" asserts that there is a conceivable agreement which would satisfy him. This is clearly not true. He is lying, because he wants to argue that his rejection of an agreement (if there is one) is the fault of the Obama administration which could conceivably have negotiated an agreement he supported.
Also note the unseriousness of "behavior change in a variety of areas". One can't obtain concessions without making clear demands. Even in a pure hypothetical fantasy, Gerson doesn't explain anything the Iranian regime could do to convince him to accept a relaxation of sanctions. I'm quite confident there is nothing they could do and sure that they would believe this if Gerson were President.
Gerson assumes that Iranians would perceive tough sanctions as the cost of Iranian irresponsibility. I think that most Iranians (including Ayatollah Khameini) have the impression that Iran is trying to normalize relations with most of the rest of the world by making concessions. To me it seems obvious that Gerson's approach will convince them that President Rouhani's approach failed. The effect of tough sanctions depends on whether they are perceived to be the price of Iranian intransigence or the pointlessness of Iranian concessions. I am sure that Gerson's approach would lead, in the short run, to a much more confrontational Iran. I dont guess what would happen in the long run, but I am willing to guess that they would have atomic bombs when it arrives.
Gerson perceives his point to be that the US can't impose tough sanctions unilaterally, so his approach requires convincing other countries that we negotiated in goood faith (while also not reaching an agreement -- in other words we shouldn't negotiate in good faith but we should trick the naive French, inexperienced English and the Americanophilic Putin). I agree with him that the Cotton approach is excellent news for Iran, since it makes it much more likely that they will only have to deal with US sanctions which the Islamic Republic has endured for almost all of its history.
Here I think part of the problem is 700 words per op-ed. Gerson can't explain an approach to Iran other than Obama's or bombs, because he is mostly writing about the folly of the 47. But I think most of the problem is that he arrived at a terrible proposal by the process of elimination. He can't agree with Obama. He doesn't think bombing will work, He doesn't support an invasion. So he's left with stick with sanctions and hope for the best.