While Allison cites Pakistan and India as proliferators, nowhere in the article does he mention Israel's nuclear arsenal. The Israeli tactic of not acknowledging its nuclear capabilities does not erase the fact that Israel's capabilities are very much a factor in the Middle East. Allison is not alone, since most loquacious commenters on proliferation in the region simply treat Israel as though it is not a factor in the regional quest for nukes.
One approach to dealing with Iran's drive for nuclear arms is for the U.S. to lend salience to ridding the entire region, including Israel, of nuclear weapons.
Also, Allison implies that Iran might think it could get away with dispensing nuclear weapons to arm's length terrorists, but this is a phony argument. Even if unambiguous proof were lacking, there is little doubt that Iran would be presumed a prime candidate. Just as some U.S. officials seized upon 9-11 as an excuse to hit Iraq, so it should be expected that following a nuclear incident in the U.S. some officials would seize the opportunity to hit Iran. This can be construed as an incentive for Iran to clarify its position rather than to cloud it.
In any case, this is a flawed analysis, made plausible only by the prevailing biases of U.S. political rhetoric.
The nightmare this time - The Boston Globe: "But just as JFK refused to choose between accepting nuclear weapons in Cuba or attacking the Soviet Union during the Cuban missile crisis, the challenge today is to find additional options, short of war, to stop Iran's acquisition of nuclear arms."