"Iran fears that US may be building its 8,500th nuclear weapon," The Onion, an American satirical magazine, recently ran this headline to draw attention to the vast nuclear arsenals of the country that is most insistent on pressuring Tehran. But there was no satire intended on Monday when President Barack Obama declared that the US "has more nuclear weapons than we need".
The US currently has 1,950 nuclear warheads deployed, but has agreed with Russia (which has 2,430, but in poorer shape and less efficient than those of their American rivals) that each side will reduce its stockpile of deployed warheads to 1,500. But Mr Obama, speaking at a nuclear security conference in Seoul, suggested that even more cuts could be made.
Reducing the US nuclear arsenal to the number of warheads it "needs" raises a question: just how many nuclear warheads does a superpower need, from a perspective of strategy rather than murderous efficiency? And the corollary: on what basis do nuclear-armed superpowers dissuade smaller, more vulnerable states from acquiring a nuclear deterrent of their own?
To make that more concrete, consider the greatest nuclear challenge: how does the US with its 1,950 deployed warheads and thousands more in reserve persuade a country such as Iran, which fears that Washington seeks to topple its regime and whose annual defence spending is about 1 per cent of the US defence budget, not to seek a nuclear deterrent as a kind of strategic trump card to ensure its survival?
For that purpose, the US and other major powers invoke the nuclear Non-Proliferation Treaty (NPT), which offers signatories international assistance in the use of civilian nuclear power in exchange for providing a verifiable commitment to refrain from weaponising nuclear material. But that's only part of the deal. The NPT also requires nuclear-armed states to "pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control".
States agree to refrain from building nuclear weapons, in other words, to give the nuclear-armed states the time and space to disarm. It hasn't quite worked out that way, as we know: since the treaty's adoption in July of 1968, the original five nuclear powers - the US, Russia, Britain, France and China - have been joined by Israel, India, South Africa (which later dismantled its nuclear bombs), Pakistan and North Korea, and the global stockpile of nuclear weapons has expanded. And nobody talks about targeting nuclear-armed countries for invasions or air strikes.
Mr Obama, like Ronald Reagan before him, appears to genuinely believe in the principle of dramatically cutting nuclear stockpiles in negotiation with the Russians, but even if they manage to agree, there's always the question of how many nuclear warheads they "need". Reductions, perhaps, but nobody imagines complete disarmament in the foreseeable future.
And that leaves a subtext of hypocrisy whenever leaders of states that claim a "need" for nuclear weapons scold others that are perceived to be trying to join their exclusive club. Consider this extract from Mr Obama's speech to the Israel lobby Aipac three weeks ago:
"A nuclear-armed Iran is completely counter to Israel's security interests. But it is also counter to the national security interests of the United States ... A nuclear-armed Iran would thoroughly undermine the non-proliferation regime that we've done so much to build."
Now bear in mind that Israel is widely assumed to have some 200 nuclear warheads, whereas Iran has none and, according to Mr Obama himself, is not currently building any, and hasn't decided to do so. Mr Obama wouldn't dream of questioning Israel's "need" to maintain its nuclear arsenal. (If he dared to, the Israelis might answer: "Why shouldn't we have a defence capability that you deem so vital to your own security?") So, Iran is essentially being warned off challenging Israel's monopoly on nuclear force in the Middle East.
But while all of Israel's Arab neighbours oppose Iran acquiring nuclear weapons, they don't accept Israel's arsenal, and are not prepared to nod and wink at it. The Obama administration learnt that the hard way during the UN's NPT review conference in May of 2010, where it had hoped to put pressure on Iran, with the help of Arab states. The administration's intensive lobbying, however, failed to restrain Egypt's Mubarak regime from instead pressing for a "nuclear-free Middle East". The Egyptians bluntly warned that Iran couldn't be confronted while turning a blind eye to Israel. "We don't think that there should be first-class countries that are acquiring nuclear weapons and second-class countries that are not," Egypt's UN ambassador, Maged Abdelaziz, said at the time. "We say that in order to be able to deal with the Iranian issue, you have to address the nuclear capabilities of Israel."
Egypt proposed that both Israel and Iran be invited to an international conference on creating a nuclear-free Middle East. The US response, at the time, from Under Secretary of State Ellen Tauscher was: "The best chance we have to achieve a WMD-free zone in the Middle East is to reach an agreement on a lasting and just peace."
Applying that logic to the current Iran stand-off, of course, would require that the US sit down with Iran to talk not about its nuclear programme, but instead to resolve the underlying conflict that might persuade Tehran to seek the bomb in the first place.
Meanwhile, the conference on making the Middle East a WMD-free zone as proposed by Egypt two years ago will, in fact, take place in Finland in December, and Israel and Iran have both been invited. Both might benefit from attending - if they've managed to avoid going to war.
Tony Karon is an analyst based in New York
On Twitter: @TonyKaron