In the midst of a boilerplate speech to the UN General Assembly on the virtues of democracy and freedom, President Obama tossed in some rhetoric on Iran that's either empty or dangerous. Neither option is a good one.

Observing that "Time and again, [the Iranian government] has failed to take the opportunity to demonstrate that its nuclear program is peaceful, and to meet its obligations to the United Nations," Obama declared that "America wants to resolve this issue through diplomacy, and we believe that there is still time and space to do so. But that time is not unlimited." Ultimately, he stated, "the United States will do what we must to prevent Iran from obtaining a nuclear weapon."

Now, perhaps this is simply empty rhetoric in the service of appearing "tough." That, especially in the midst of an election campaign, would hardly be without precedent. For that matter, both he and his predecessor have issued similar statements for years now with very little in the way of follow-through.

Alternatively, it's possible that the president is serious. Perhaps there is an unspoken deadline or red line at work here and "what we must" is an imminent option rather than something that merely sits on an imaginary table.

A third option is that Obama thinks he's talking tough but that continually doing so is backing him into a corner that makes escalation into an undesired war inevitable. That's what happened with the Afghan surge, after all: years of stump-speech rhetoric about necessary wars and unacceptable outcomes made acknowledging an unpleasant reality politically unacceptable.

Regardless, the president's declaration at the UN is based on a bizarre premise: "Make no mistake: a nuclear-armed Iran is not a challenge that can be contained."

Why on earth not? In the sixty-seven-year history of atomic and nuclear weapons, they have been deployed precisely twice. Both by the United States. Both in the context of a world where no other country possessed such weapons. Both in the first three days of the nuclear era. In the sixty-seven years and change since the dropping of Fat Man over Nagasaki, no bomb has been detonated other than for testing.

During that time, some truly evil and unstable governments have had nuclear weapons at their disposal and were successfully deterred from using them even when they used conventional weapons against their enemies. Joseph Stalin. Mao Zedong. Kim Jong Il.

Both sides of the perennial India-Pakistan conflict have nukes and have resisted escalating to anywhere near using them despite all manner of cross-border provocations.

Obama also declared that a nuclear Iran "would threaten the elimination of Israel, the security of Gulf nations, and the stability of the global economy." But that's absurd. The Iranian mullahs may appear crazy from a Western perspective but, after more than three decades in power, they've demonstrated quite clearly that, above all else, they value staying in power. What could they possibly have to gain from a nuclear exchange with Israel?

Aside from some far-fetched regional war that disrupted the flow of oil, it's hard to imagine that "the global economy" would react one way or the other to a nuclear Iran. If it can survive numerous nuclear Kims in a row, one imagines it'll cope just fine with some nuclear ayatollahs.

Finally, Obama contends, a nuclear Iran "risks triggering a nuclear-arms race in the region, and the unraveling of the non-proliferation treaty." But while there's no question that the Sunni Arab leadership in the neighborhood wishes very much to avoid their Shiite Persian neighbors going nuclear, surely the same was true with regard to the Israelis. Thus, it's quite unclear why a nuclear Iran would be a tipping point.

As for Obama’s concern about the integrity of the Nuclear Non-Proliferation Treaty (NPT), can we please stop pretending that it's a serious deterrent? India, Pakistan, North Korea and Israel have all successfully tested weapons outside the NPT's protocols with little in the way of international repercussion. Most advanced states could acquire the weapons relatively quickly if they so choose.

Alas, this is yet another area in which November's election does not offer a choice. Indeed, the Republican nominee's position statement on Iran could have been cribbed from Obama's speech:

Mitt Romney believes that it is unacceptable for Iran to possess a nuclear weapon. Should Iran achieve its nuclear objective, the entire geostrategic landscape of the Middle East would tilt in favor of the ayatollahs. A nuclear Iran will pose an existential threat to Israel, whose security is a vital U.S. national interest. As Iran’s ballistic missile capacity improves, it will endanger Europe and eventually the continental United States. It will provoke an arms race in which the Arab nations themselves forge ahead with nuclear programs of their own. The result will be a nightmarish cascade of nuclear tensions in the world's most volatile region.

Romney is actually more explicit than Obama on what to do to prevent this implausible scenario, not only putting "a military option" on the proverbial table but calling for "restor[ing] the regular presence of aircraft carrier task forces in both the Eastern Mediterranean and the Persian Gulf region simultaneously."

All this talk of using force comes despite the fact that it contradicts a near-universal consensus among the experts: no politically plausible military action will be able to do more than postpone Iran's successful deployment of nuclear weapons and will simultaneously bolster the regime while weakening pro-Western sentiments among the Iranian people.

At least at the level of presidential rhetoric, insanity on the Iran question is a matter of bipartisan consensus.

James Joyner is managing editor of the Atlantic Council.