During last night’s presidential debate, Donald Trump and Hillary Clinton were asked about their positions on U.S. nuclear policy. In particular, they were asked whether or not they believed that the United State should adopt a policy of “No First Use” (NFU). Basically, adopting an NFU doctrine would entail the United States informing the world that it would never use nuclear weapons first. This means that the only scenario in which the President of the United States would authorize a nuclear strike would be in retaliation to another country’s nuclear attack on the U.S. or a U.S. treaty ally. Unfortunately, neither candidate answered this question at all. Trump responded by going on an incoherent rant for two minutes because, as demonstrated by his response to Hugh Hewitt’s question about the triad, he knows nothing about America’s nuclear arsenal. Literally… he knows nothing. It was, therefore, frustrating that Clinton also refused to answer the question, as I think it would have further illustrated just how pathetically uninformed Trump is. To be fair, though, she may well have forgotten the original question while listening to Trump’s incoherent babble.
Deciding whether the U.S. should adopt an NFU policy is a very tough question. There is no clear consensus among nuclear weapons and non-proliferation experts, and it is difficult to model and account for all of the second order effects an NFU declaration might cause. That being said, I think that committing to an NFU policy is, on balance, the right choice. I want to hedge slightly because I do think there are compelling arguments for maintaining the ability to launch a nuclear first strike. Nevertheless, I think arguments against NFU rely on highly implausible scenarios and are thus fairly unpersuasive.
So, why do I support the adoption of an NFU doctrine? First, I think that it would heighten crisis stability. Currently, there is nothing preventing the United States from deploying nuclear weapons at a whim. Indeed, U.S. national strategy explicitly reserves the right to unilaterally launch nuclear weapons if it is deemed to be in the strategic interests of the United States. Because of this, other countries can never be sure that the U.S. won’t nuke them. Were a crisis to escalate between the U.S. and another country, it is possible that the other country might miscalculate out of fear of an impending first strike. Thus, instead of deterring conflict, the threat of a nuclear first strike might instead lead to escalation as countries face “use it or lose it” pressures. Second, I think adopting an NFU doctrine would enhance U.S. credibility regarding the NPT, as that treaty calls for nuclear states to move towards disarmament. Now, I’m highly skeptical that this will ever happen. In fact, I evaluate the probability of a nuclear-free world to be somewhere below .1%. Nevertheless, verbally accepting meaningful constraints on U.S. nuclear weapons use would reassure other non-nuclear states that the U.S. is committed to reducing the risk of an accidental nuclear war and takes its NPT commitments seriously (at least as seriously as every other nuclear signatory of the treaty). This would enhance U.S. credibility when negotiating with states considering nuclear acquisition because it prevents charges of hypocrisy and thus keeps the U.S. on the moral high ground. This might seem irrelevant, but it is actually quite important. For example, China is justifying its illegal SCS territorial claims in part by arguing that U.S. legal protests lack credibility because the U.S. is not a signatory of UNCLOS. Treaties and verbal pledges may just be rhetorical commitments, but in our legalistic, interconnected world, they do play a meaningful role in shaping and constraining states.
There is, however, one very good argument against adopting an NFU doctrine: stopping a large-scale conventional force. This argument was originally made during the Cold War, when Warsaw Pact forces severely outnumbered NATO forces in Central Europe. The U.S. and its allies were pessimistic about their ability to halt a Soviet invasion of West Germany, so the Kennedy administration developed a nuclear strategy designed to blunt a Soviet invasion. Known as Flexible Response, this strategy allowed for tactical nuclear weapons to be deployed against large Soviet armored formations. In other words, if the Soviets ever tried to invade Germany, the U.S. and its allies would have dropped nuclear bombs onto advancing Soviet troops to prevent them from overrunning Western Europe. In theory, this might be a legitimate reason to initiate a nuclear first strike. However, there are two arguments that undercut this defense of retaining nuclear flexibility. First, there simply isn’t a plausible scenario in which the U.S. and its allies would be overrun by a conventionally superior foe. Indeed, the only possible situations I could imagine would be a Russian invasion of the Baltics or a North Korean invasion of the South. For a number of reasons, neither scenario seems plausible. Moreover, one must weigh the costs of nuclear escalation. Yes, it would be catastrophic if Estonia, Latvia, and Lithuania fell to Vladimir Putin, but it’s not clear to me that their security is worth an escalation to tactical and, worst case scenario, strategic nuclear warfare. In short, neither Russia nor North Korea has an incentive to start a war against the United States, and if they do decide to invade American allies, the United States can beat them with purely conventional forces. While it’s true that nuclear first use might be necessary in theory, the current threat environment is permissive enough to allow for the adoption of an NFU posture.
There are a few other arguments against adopting an NFU policy. One is that it undermines allies’ confidence in U.S. security guarantees, and the other is that an NFU declaration is disingenuous because there would likely still be some extreme scenarios in which the U.S. might consider nuclear first use (for example, if Russian tanks were about to role through Paris). I’m somewhat skeptical of these arguments, though, as the first one is not well-supported by any empirical evidence, and the second one seems entirely irrelevant. Seriously, who cares if the U.S. is being disingenuous? Obviously states know that if they invade Western Europe or the American homeland, they will likely face a nuclear response. This is largely irrelevant, though, as there is no plausible scenario in which this occurs. What matters is proxy conflicts in which U.S. nuclear threats are less clear. A commitment to no first use would be far more credible in these situations, and thus formally declaring a policy of no first use would yield meaningful returns in the form of greater crisis stability.
Obviously, the question of whether the U.S. should declare an NFU policy is a tough one, and reasonable people can disagree. Hopefully I’ve made a decent case for my position, but I certainly admit that I might be wrong. Ultimately, the point of this post is to encourage you to think about nuclear weapons doctrine because depite the Cold War ending two and a half decades ago, nuclear weapons still play a major role in world politics. So, when we ignore questions of nuclear strategy – or worse, vote for people who don’t even understand the basics of the American nuclear arsenal – we are asking for real trouble.