President Trump should urgently clarify that any Russian use of nuclear weapons against a NATO member state will result in at least commensurate U.S. nuclear retaliation.
That statement is necessary for two reasons. First, because Russia is developing and deploying low-yield nuclear weapons that it might use for battlefield strikes against NATO military forces. Russia hopes these weapons would allow it to achieve tactical effect (destroying NATO forces) without provoking NATO nuclear retaliation. And while, against Democratic opposition, the Trump administration is rightly developing a U.S. counterforce to the Russian systems, it won’t be deployable for a number of years.
The second problem is that neither the U.S. nor NATO presently has a clear response to this Russian weapons-strategy. Evidencing as much on Tuesday, Sen. John Cornyn, R-Texas, raised his concerns to the nation’s top intelligence chiefs. Responding to Cornyn, the testifying intelligence chiefs noted that policymakers are responsible for clarifying deterrent policy against Russia’s new threat. That clarity gap represents a dangerous opening in NATO security. And we know that Russian President Vladimir Putin is a master at taking advantage of strategic gaps. Note, for example, the Russian president’s breach of the Intermediate-Range Nuclear Forces Treaty.
The U.S. must take the lead in filling in the gap because NATO seems reluctant to do so.
Speaking to the Washington Examiner Sunday, NATO Secretary General Jens Stoltenberg was clear about the risk Putin’s moves pose. They reduce the threshold for use, he noted, and increase “the likelihood of any use of nuclear weapons in a conflict.” Stoltenberg explained that “the concept or the idea of these kind of weapons is to try to delink European security from U.S. security, and to underpin the idea of a kind of limited nuclear war. Which is extremely dangerous — these weapons can only reach Europe.”
The NATO chief added that the high-mobility of these systems means they can be more easily hidden from detection. All of this matters because it fits a pattern of Russian investment in capabilities that offer real facilitation for a Russian invasion of NATO states. Seeing as Russia doesn’t have much money, we have to pay heed to whatever military platforms it chooses to invest in.
Yet although Stoltenberg’s analysis is good, his proposed response is not. When I asked whether he would welcome a statement from NATO nuclear powers (the U.S., Britain, and France) that these Russian deployments do not change the existing principle of NATO strategic nuclear deterrence — namely, that any Russian nuclear attack will result in a U.S. nuclear response — Stoltenberg said no. The secretary general instead suggested that Moscow recognizes existing NATO nuclear deterrence remains viable and so “there is no urgent need for a new statement … there is no doubt that NATO’s nuclear deterrence is valid.”
As with U.S. intelligence chiefs, I believe Stoltenberg is wrong. Indeed, the NATO chief admits as much when he notes that the entire premise of Russian strategy with these weapons is to offer war-fighting potential short of full-nuclear escalation. If the Russians believe they can take tactical nuclear shots without a response, that’s all that matters.
Still, there’s a simple way to address this threat. President Trump, British Prime Minister Theresa May, and French President Emmanuel Macron should issue a statement that any nuclear attack on any NATO member state by forces or intermediaries of the Russian Federation will result in commensurate or escalated nuclear retaliation. Considering that NATO retains nuclear strategic dominance over Russia, such a statement will put Putin back in his box.

