Should Iran get the bomb, a new report (pdf) doubts that Saudi Arabia will follow suit:
The Saudis would be highly motivated to acquire some form of nuclear deterrent to counter an Iranian bomb. However, significant disincentives – including the prospect of worsening Saudi Arabia’s security environment, rupturing strategic ties with the United States, damaging the country’s international reputation and making the Kingdom the target of sanctions – would discourage a mad rush by Riyadh to develop nuclear weapons. And, in any case, Saudi Arabia lacks the technological and bureaucratic wherewithal to do so any time in the foreseeable future. Saudi Arabia is more likely to respond to Iranian nuclearization by continuing to bolster its conventional defenses against Iranian aggression while engaging in a long-term hedging strategy designed to improve civilian nuclear capabilities.
Lynch sees holes in this theory:
The argument is well-made, but I see some key points which remain unresolved. India and Pakistan got away with going nuclear, oil behemoth Saudi Arabia is hardly a prime target for economic sanctions, and Washington doesn’t have a great track record of standing up to Riyadh. What’s more, the authors probably overestimate the rationality and coherence of Saudi foreign policy, which might leap forward out of status concerns or irrational terror of Tehran despite the compellingly logical reasons they shouldn’t.