Another wildcard is the future of variable- or low-yield nuclear weapons. Russia has perhaps 2,500 of these smaller nukes, according to Hans M. Kristensen of the Federation of American Scientists. Russian doctrine contemplates using mini-nukes to secure tactical victory on an otherwise conventional battlefield, reasoning that the United States would be unwilling to strike back with a much larger weapon that might, say, also destroy a nearby city. The Pentagon calls this the \u201cescalate to de-escalate<\/a>\u201d\u00a0doctrine.<\/p>\n The United States is starting to build a new generation of smaller nukes of its own. The reasoning was laid out in the 2018 Nuclear Posture Review<\/a>, and the weapons have been rolling off<\/a> the assembly line since\u00a0January.<\/p>\n \u201cA limited number of low-yield nuclear weapons provides the president with an option where we can say, \u2018If the Russians attacked us with a low-yield nuclear weapon, we have an option to reply in kind that is inherently de-escalatory and stabilizing\u2019,\u201d Selva\u00a0said.<\/p>\n But Selva also noted that low-yield weapons present the same sort of ambiguity as hypersonic\u00a0weapons.<\/p>\n \u201cWe don\u2019t know what they launched at us until it explodes,\u201d he\u00a0said.<\/p>\n The U.S.<\/span> military has responded to Russian weapons development with several other key moves: building a next-generation air-launched cruise missile, hiring Northrop Grumman to build a new penetrating bomber, lowering the nuclear yield on some sub-launched ballistic missiles, and exploring bringing back a sea-launched cruise missile, or SLCM<\/span>, that could have a nuclear\u00a0tip.<\/p>\n \u201cThis suite of systems will provide capabilities that enable the United States to threaten limited response options of varying sizes against targets throughout Russia and, if needed, against deployed Russian forces,\u201d according to a March report<\/a> from the Center for Naval Analysis, or\u00a0CNA<\/span>.<\/p>\n A senior Defense Department official said a new SLCM<\/span> might add to the nation\u2019s arsenal of low-yield nukes, or simply replace current warheads if arms-control agreements\u00a0require.<\/p>\n Warhead numbers are less important than they used to be. The U.S.<\/span> isn\u2019t interested in matching Russia\u2019s number of small-yield bombs. It doesn\u2019t have to. One of the benefits of having lots of ambiguous weapons is that all of your missiles and bombs become a bit more\u00a0threatening.<\/p>\n \u201cThey have many more than we do, that\u2019s true,\u201d said Selva of the low-yield nuclear bombs. \u201cBut we now have a way to answer that threat. It\u2019s important to have that as part of our option\u00a0set.\u201d<\/p>\n Lynn Rusten, vice president of the Global Nuclear Policy Program at the Nuclear Threat Initiative, said that the ambiguity problem would apply to the SLCMs effort as well. \u201cWe use conventional\u00a0SLCMs a lot in our normal warfare. If you start having nuclear SLCMs deployed as well, there will be a real discrimination in terms of when one of those things is launched, what is that thing coming at you? Where is it\u00a0going?\u201d<\/p>\n As new weapons inject new uncertainty into nuclear strategy, the Trump administration\u2019s main responses have been to tear up<\/a> one arms-control treaty, remain non-committal<\/a> on extending another, and to propose a third: a new, comprehensive nuclear-weapons agreement between China, Russia, and the United\u00a0States.<\/p>\n After his Tuesday meeting with Lavrov, Pompeo said Trump had \u201ccharged his national security team to think more broadly about arms control, to include countries beyond our traditional U.S.-Russia framework and a broader range of weapon systems. The president wants serious arms control that delivers real security to the American people. And we know \u2013 and I think we agree on this \u2013 to achieve these goals, we\u2019ll have to work together, and that it would be important that, if it\u2019s possible, we get China involved as\u00a0well.\u201d<\/p>\n But experts say Beijing has no interest in such an agreement. For one thing, its nuclear arsenal is far smaller than the U.S.<\/span> and Russian ones \u2014 though it has recently developed a ballistic-missile submarine fleet<\/a> and is outpacing<\/a> the United States in\u00a0hypersonics.<\/p>\n \u201cChina\u2019s longstanding policy is that it will join the process once Washington and Moscow have completed deep and irreversible reductions and foresworn the right to use nuclear weapons first,\u201d the CNA<\/span> report\u00a0said.<\/p>\n The report also notes that Beijing would be reluctant to submit to the kind of transparency and verification arrangements that make arms-control treaties\u00a0work.<\/p>\n<\/div>\n<\/article>\n<\/div>\n \u201cIn China\u2019s policy, opacity makes a major contribution to the survivability of its smaller nuclear force. Chinese policy statements often assert that the United States, as the stronger power, has an obligation to be transparent about its capability, while China is entitled to opacity because disclosing more detailed information about the size, composition, geographic locations, and planned trajectory of its nuclear posture would create operational vulnerabilities,\u201d it\u00a0said<\/p>\n Many arms control experts say<\/a> the first and most important step that the U.S.<\/span> could take in navigating this far more unpredictable future is to extend New START<\/span>. Even Selva, who declined to offer a public recommendation about such an extension, said that the United States\u00a0benefits in multiple ways from the treaty\u2019s mechanisms for keeping track of the parties\u2019 strategic arsenals. \u201cThe treaty is what the treaty is. Does the extension of the treaty accrue to our national interest? That\u2019s the only question we should ask. If we choose not to extend the treaty we live in a world without an accountable set of numbers. Does that accrue to our national interest? That is the way I believe we should have this debate,\u201d he\u00a0said.<\/p>\n The CNA<\/span> paper goes further, saying that the treaty is a bulwark against inefficiency, ignorance, and ultimately,\u00a0unpredictability.<\/p>\n \u201cWithout New START<\/span>\u2019s cooperative transparency practices, the U.S.<\/span> intelligence community would likely devote more resources to monitoring Russian strategic nuclear forces but have less insight and less confidence in its analytical judgements,\u201d it said. \u201cThe United States would face an opportunity cost of diverting scarce national technical means (NTM<\/span>), such as satellites, and technical analysts from other missions. Russian defense officials would also navigate increased uncertainty and lose the ability to confirm that the United States has not reversed its New START<\/span> reductions. Neither country would have the same degree of confidence in its ability to assess the other\u2019s precise warhead levels. Worst-case scenario planning is also more likely as a\u00a0result.\u201d<\/p>\n The administration\u2019s internal policy debate has begun to anger some lawmakers. On Wednesday, the Senate Foreign Relations Committee heard testimony from Undersecretary of State for Arms Control and International Security Andrea L. Thompson. She said renewing New START<\/span> might not be in the best interests of the country, and that the administration was looking at it. But she declined to\u00a0elaborate.<\/p>\n So Sen. Bob Menendez, D-N.J., asked her, \u201cIf New START<\/span> expires could Russia target the United States with hundreds or possibly thousands of additional nuclear\u00a0warheads?\u201d<\/p>\n Thompson responded that that was a good question for Russia but she wasn\u2019t going to answer hypothetical\u00a0questions.<\/p>\n<\/div>\n<\/article>\n<\/div>\n Menendez exploded. \u201cIt\u2019s not a hypothetical. It\u2019s what would happen if we cannot verify what they\u2019re\u00a0doing.\u201d<\/p>\n A collapse of New START<\/span> might also cause China to embrace a more aggressive nuclear stance to hedge against rising\u00a0unpredictability.<\/p>\n Tong Zhao, a fellow in Carnegie\u2019s Nuclear Policy Program at the Carnegie\u2013Tsinghua Center for Global Policy, wrote<\/a> that the treaty\u2019s end could \u201cincrease Chinese uncertainty about the sizes of U.S.<\/span> and Russian strategic nuclear arsenals and so exacerbate China\u2019s concerns about their numerical growth. Second, a lack of transparency would lead the U.S.<\/span> and Russian arsenals to grow faster than they otherwise would, and lead China to attribute such growth to more aggressive intentions of the two big nuclear\u00a0powers.\u201d<\/p>\n As uncertainty increases, misperceptions become more dangerous. And there is reason to believe the United States is already looking at the situation through various imperfect lenses. One is the belief that China has any interest in trilateral arms control. Another is \u201cescalate to de-escalate.\u201d Some Russia experts, such as Olga Oliker, the Europe and Central Asia director at the International Crisis Group, call it a fiction dreamed up in the West after a misreading of a Russia\u2019s 2017 Naval\u00a0Doctrine.<\/p>\n \u201cMoscow continues to believe, and Russian generals in private conversations emphasize, that any conventional conflict with NATO<\/span> risks rapid escalation without \u2018de-escalation\u2019 \u2014 into all-destroying nuclear war. It must therefore be avoided at all costs,\u201d she wrote<\/a> in\u00a0February.<\/p>\n \u201cIf anything, U.S.<\/span> emphasis on new lower-yield capabilities \u2014 effectively an \u2018escalate to de-escalate\u2019 strategy of the sort many attribute to Russia \u2014 would undermine the deterrent balance, potentially triggering the very sorts of crises low-yield proponents hope to\u00a0avert.\u201d<\/p>\n Michael Kofman, a senior research scientist at CNA<\/span>, says the \u201cescalate to de-escalate\u201d debate obscures a more fundamental truth about Russian strategic doctrine. \u201cRussia has never accepted the proposition that a war with the United States could be conventional only. Hence, Russian nuclear strategy has a firm place for scalable employment of nuclear weapons, for demonstration, escalation management, warfighting, and war termination if need be,\u201d he told Defense One.<\/em> \u201cThe gist of the problem is that the Pentagon believes that nuclear weapons are some kind of gimmick that can be deterred in conventional war, but actually the prospect for conventional-only war with Russia is somewhat limited from the\u00a0outset.\u201d<\/p>\n Bottom line: the U.S., Russia, and China, may be entering into a high-stakes discussion on nuclear arms with each suffering from severe misconceptions about the others\u2019 intent. The price of failure of the new negotiation effort, if New START<\/span> is not re-affirmed, would be a new period of heightened nuclear tensions and less\u00a0predictability.<\/p>\n Rusten believes the arms race has already\u00a0begun.<\/p>\n \u201cWe don\u2019t want to be where that trajectory will take us five years from now,\u201d she\u00a0said.<\/p>\n