Walter Russell Mead connects the Russian incursion in the Crimea to the Libyan war to draw a general lesson about the general utility of a nuclear deterrent:

When Ukraine escaped from the Soviet Union in 1990, Soviet nukes from the Cold War were still stationed on Ukrainian territory. After a lot of negotiation, Ukraine agreed to return those nuclear weapons to Russia in exchange for what (perhaps naively) its leaders at the time thought would be solid security guarantees from the United States and the United Kingdom. The “Budapest Memorandum” as this agreement is called, does not in fact require the United States to do very much. We can leave Ukraine twisting in the wind without breaking our limited formal obligations under the pact.

If President Obama does this, however, and Ukraine ends up losing chunks of territory to Russia, it is pretty much the end of a rational case for non-proliferation in many countries around the world. If Ukraine still had its nukes, it would probably still have Crimea. It gave up its nukes, got worthless paper guarantees, and also got an invasion from a more powerful and nuclear neighbor.

The choice here could not be more stark. Keep your nukes and keep your land. Give up your nukes and get raped. This will be the second time that Obama administration policy has taught the rest of the world that nuclear weapons are important things to have. The Great Loon of Libya gave up his nuclear program and the west, as other leaders see it, came in and wasted him.

It is almost unimaginable after these two powerful demonstrations of the importance of nuclear weapons that a country like Iran will give up its nuclear ambitions. Its heavily armed, Shiite-persecuting neighbor Pakistan has a hefty nuclear arsenal and Pakistan’s links with Iran’s nemesis and arch-rival Saudi Arabia grow closer with every passing day. What piece of paper could Obama possibly sign—especially given that his successor is almost certainly going to be more hawkish—that would replace the security that Iran can derive from nuclear weapons? North Korea would be foolish not to make the same calculation, and a number of other countries will study Ukraine’s fate and draw the obvious conclusions.

This analysis is, on the surface, extremely persuasive. Which is exactly why I think it deserves a closer, more critical look.

First, let’s look at the proposition with respect to Ukraine specifically. Was it even plausible that Ukraine could have held on to an independent nuclear deterrent after the collapse of the Soviet Union? The answer is almost certainly, “no.” Indeed, it’s hard to imagine any action that would more greatly have imperiled the stabilization of the post-Soviet order than such a determination on Ukraine’s part. Western and Russian interests were aligned in wanting to see Ukraine denuclearized; an independent nuclear Ukraine would have been treated as a dangerous rogue state. Russia’s ability to project power in the immediate aftermath of the collapse of the Soviet Union was extremely limited, but Ukraine’s ability to defend itself was even more ephemeral. The best evidence that Ukraine had no real choice but to denuclearize is precisely that Ukraine got almost nothing in exchange for agreeing to hand over its Soviet nuclear weapons.

Assuming, for the sake of argument, that a nuclear Ukraine was a real possibility, how would it have responded differently to the events of the past few weeks? Nuclear weapons would not have changed the election results that brought a pro-Russian premier to power – though they would dramatically increase Russian interest in ensuring a pro-Russian Ukraine. By the same token, nuclear weapons would not have deterred ethnic Ukrainians from taking to the streets. If events continued to play out as they have, and Russia sent troops to Crimea, nuclear saber-rattling against Russia would be completely specious; nobody would believe such a transparently suicidal threat. How would nuclear weapons avail Ukraine in the current crisis? What seems most likely to me is that, if Ukraine had an independent nuclear deterrent, Putin would have intervened much earlier to make sure that Yanukovich remained in power. He certainly wouldn’t risk a Ukrainian nuclear deterrent falling into the hands of an anti-Russian party.

That point can be generalized. There is considerable evidence that a nuclear deterrent does not suffice to prevent either conventional conflict with other states, or violations of a country’s sovereignty, or regime change. Israel’s nuclear deterrent dates to the 1960s, but did not prevent the surprise Syrian-Egyptian attack in 1973. South Africa’s nuclear deterrent dates to the 1970s, but did not prevent the dissolution of the apartheid regime (which voluntarily denuclearized to prevent its arsenal falling into the hands of the ANC). Pakistan’s nuclear deterrent dates to the 1990s, but did not prevent America from toppling its Afghan ally, or conducting drone warfare and engaging in covert operations within Pakistani territory, including the assassination of Osama Bin Laden. Most obviously, the enormous Soviet nuclear arsenal was of no utility in preventing the sudden and spectacular collapse of the Soviet regime. (Nor, for that matter, was the Russian nuclear deterrent useful in deterring Western intervention to dismember Serbia, a traditional Russian ally.)

Dictators may well learn the lesson from Libya that denuclearization will not bring Western protection – which is true. It does not therefore follow that a nuclear Libya could have done anything different to defeat its insurgency. It is likely that Western powers would have been much more reluctant to initiate a bombing campaign – a suicidal threat would have more credibility coming from a man literally fighting for his life – but, on the other hand, Western powers would have a much, much greater incentive to be involved in a Libyan civil war if there was a question of the ultimate disposition of nuclear weapons. Consider: would America take a hands-off attitude to civil war in Pakistan? It seems to me we would likely be more involved in such a civil war than we are in Syria’s, precisely because the disposition of a nuclear arsenal would be at issue.

The primary utility of nuclear weapons is to deter other nuclear powers from escalating to nuclear warfare. Secondarily, nuclear weapons are useful as a deterrent to conventional war if they can be plausibly deployed in a tactical fashion against a foreign invasion. So: U.S. plans for fighting World War III involved the first use of tactical nuclear weapons against Soviet armor, either in Germany or in Poland. Would the Soviet Union have escalated from that event to a suicidal strategic nuclear exchange? American war planners obvious thought not. Similarly, Pakistan could use tactical nuclear weapons on its own territory against an invading Indian army. That prospect may have deterred India from launching a massive invasion of Pakistan in response to any number of provocations. Nuclear weapons are not useless, in other words, but their utility is distinctly limited.

What are the implications for Iran or North Korea? I doubt either Iran or North Korea were particularly inclined to trust pieces of paper in the first place. The rational case for Iran to go nuclear can only be countered by a rational case to not go nuclear – concrete interests that could be secured by an agreement, concrete risks to refusing to come to an agreement. Perhaps the prospect of full normalization – which would have very substantial economic benefits for Iran – would be enough carrot, while the prospect of continued isolation, being the object of covert warfare, and the risk of Saudi Arabia going nuclear in response to an Iranian bomb are sufficient stick. Perhaps not. North Korea is much tougher because there is no plausible path forward for the regime within the world community of nations, so there’s not much that can be offered as a carrot.

But the more important point lies elsewhere. Mead says that if Obama “allows” Ukraine to be dismembered, then other countries will draw the lesson that if you want to prevent the same from happening to you, you’d better get a bomb. But even if an aggressive American response were effective in securing Crimea for an independent, pro-Western Ukraine (which I don’t believe it would be), the lesson a country like Iran would draw is certainly that America successfully intervened to secure regime change in Ukraine, and is therefore undoubtedly still determined to do the same in Iran. That is to say, it’s more likely the Iranian regime would identify with Russia than with Ukraine in this situation.

The conclusions are not mutually-exclusive, of course. Iranian hard-liners could interpret any attempt to find a negotiated solution to the crisis in Crimea as proof that the West responds well to force, while also finding any attempt to force Russia to withdraw from Crimea as proof that negotiations with the West are pointless (after all, Yanukovych negotiated a deal with the opposition under Western auspices, and the opposition simply broke the deal). But if Mead is trying to make a case that a more forceful Administration response to the situation in Crimea would be reassuring to Iranians inclined to negotiate in good faith, I think he’s kidding himself.