BRUSSELS — NATO military officials are exploring whether to upgrade their defenses to make them capable of shooting down newly deployed Russian intermediate-range nuclear missiles after a landmark arms treaty dissolves next month, according to three European officials.
Any change to the stated mission of NATO’s current missile defense system — aimed at threats from outside the region, like Iran — would probably divide the alliance’s member countries and enrage Russia, which has long said it views NATO’s missile defense site in Romania and one under construction in Poland as a threat to its nuclear arsenal and a source of instability in Europe.
“It would be a point of no return with the Russians,” said Jim Townsend, a former Pentagon official and expert on the alliance. “It would be a real escalation.”
The United States announced in February its intention to withdraw from the 31-year-old Intermediate-Range Nuclear Forces Treaty, signed in 1987 in the waning years of the Cold War, citing Moscow’s years of violations, a step the NATO alliance supported.
The treaty, which prohibits missiles with a range of 310 to 3,420 miles from Europe, will be terminated on Aug. 2 unless Moscow and Washington come to agreement to revive it in the next few weeks.
NATO ambassadors will make one last attempt to push Russia to withdraw its new cruise missiles and revive the treaty on Friday in Brussels.
Discussions about new missile defense measures are at their earliest stages, officials cautioned. NATO’s chief spokeswoman, Oana Lungescu, denied that any studies of the feasibility of upgrading the ballistic missile defenses were underway. She said the alliance had repeatedly made clear that the existing ballistic missile defense system “is neither designed nor directed against Russia.”
But the alliance is considering new air and missile defenses, Secretary General Jens Stoltenberg announced last week without revealing details. And given the rising threat of the Russian cruise missiles, NATO members are expected to order the alliance to study defense options, either after the October defense ministers’ meeting or the December leaders’ summit, a senior alliance official said.
Such an order would require all 29 allies to agree to it. But some officials think that if the treaty ends, the allies will at least be willing to examine the options. The senior official said that if the allies ultimately could not agree on shifting the mission of the ballistic missile defense sites, they may be open to a compromise that would introduce new systems to defend against Russian cruise missiles.
The push for improved defenses is fueled by Russia’s fielding of a new class of missiles as well as the expected demise of the treaty — a casualty of deteriorating relations between Russia and the United States. Eastern European countries, particularly Poland and the Baltic states, believe they are under growing threat of nuclear bullying by Moscow and have been eager to see the alliance develop new defenses.
Based on intelligence from multiple allied agencies, NATO countries have forged a consensus that the new Russian nuclear-capable cruise missiles pose a threat. The missiles, some American and European analysts fear, could give Moscow significant leverage, using the threat of attack to force other countries to de-escalate or give in to Russian demands during a crisis.
The relationship between Russia and the West has spiraled downward since Moscow’s 2014 annexation of Crimea. Russia’s destabilization of Ukraine forced the alliance to reinforce its eastern flank with new troop deployments and military exercises. Moscow responded with its own military upgrades, ultimately including the deployment of a new class of ground-based cruise missiles that the West said violated the I.N.F. treaty. Russia’s election interference, its intervention in Syria and the attempted poisoning of a former Russian intelligence officer in Britain further heightened tensions.
Any move by NATO to redirect its missile defenses or expand its system with new capabilities could be a tipping point. Russians have never believed the alliance’s denials that its interceptor system would not eventually be used to shoot down Russian missiles. The system has remained a persistent irritant for Moscow, which questioned why the alliance still needed it after Iran agreed in 2015 to pause its nuclear enrichment program and threatened to direct missiles at the alliance interceptor sites.
Officials at Russia’s NATO embassy did not return requests for comment.
Last week, allied defense ministers approved an examination of potential responses to the Russian deployment of so-called SSC-8 cruise missiles, the weapon NATO accuses Moscow of deploying in violation of the treaty, according to three NATO officials. They include expanding existing deterrence exercises and publicizing the alliance’s nuclear exercises, which are highly secretive. Drawing more attention to the allied nuclear exercises and arsenal would help deter Moscow’s use of its own weapons, some officials think.
NATO will probably need to examine more broadly what defenses it needs against the cruise missiles. Such work, if approved this year, would include exploring whether it can upgrade its Aegis Ashore radar and interceptor sites in Romania and Poland and looking at new radar or air defense capabilities against the cruise missiles.
Upgrading existing ballistic missile defense capabilities, including its two Aegis Ashore sites, would be complex. The NATO Aegis systems in Romania and Poland are incapable of firing the interceptor used to strike intermediate-range missiles. And given their close positions to Russia, the systems have significantly less time to detect, lock onto and attempt to intercept the missiles.
The United States Missile Defense Agency has examined how existing Aegis Ashore missile defense systems could be upgrade with new radar, software and interceptors to allow them to strike intermediate ballistic missiles and potentially cruise missiles, according to current and former officials briefed on the discussions.
Newer technologies like high-velocity projectiles and directed-energy lasers are likely to provide a far better defense long term, experts said. Ballistic missile defenses intercept missiles high in the atmosphere, while cruise missiles fly relatively low to the ground.
Fielding new systems to defend against a cruise missile threat, rather than upgrading the existing ballistic missile defense, may also prove more politically palatable. “If NATO is to update its systems, it may undermine its yearslong claim that the launchers were never meant to counter Russia,” said Bruno Lété, a defense analyst in the Brussels office of the German Marshall Fund of the United States.
But many Europeans see themselves as in the line of fire with the new Russian cruise missile deployments, he said. “There is a clear incentive for NATO to see if they can upgrade the existing systems to counter Russian intermediary missiles,” Mr. Lété said. “From a military perspective, this would be a relatively simple, decisive and cost-effective step.”
Russian military doctrine, according to American and European military strategists, is increasingly focused on using limited nuclear strikes to quickly end a potential conflict in Moscow’s favor. Such a use of nuclear weapons for a battlefield effect is unthinkable to European politicians and has made some allied officials more open to examining the practicality of using the existing missile defense system to defend against Russia.
“We want to make sure the Russians don’t want to exercise nuclear blackmail, and missile defense is the way to take away that intimidation, to deter that intimidation,” Mr. Townsend said.
American officials have focused on trying to deter Russian intermediate-range missiles by quickly developing their own ground-launched cruise missile, a class the I.N.F. treaty has banned. Many in the alliance oppose deploying new offensive weapons. NATO planners are not expecting a directive to add offensive capabilities, only to expand defensive measures, the senior allied official said.
Since April, the Aegis site in Romania has been undergoing an upgrade. Officials said it was long planned and did not involve recalibrating the system.
If the alliance wants to counter Russian cruise missiles, it may make more sense to deploy new technologies like directed-energy lasers, microwaves or electronic warfare measures, said Mark Gunzinger, an analyst at the Center for Strategic and Budgetary Assessments.
“We have invested in ballistic missile defenses, but frankly the cruise missile threat is a growing threat and we just haven’t fielded the capabilities to deal with it,” Mr. Gunzinger said.
Even if the alliance opts not to upgrade its Aegis Ashore sites, Mr. Gunzinger said, Russia’s new weapons will force it to field new air and missile defenses. Without them, it would be difficult to reinforce its front-line troops during a conflict, he said.
“Deterring Russia is going to take a different posture in Europe,” Mr. Gunzinger said. “It will take air and missile defenses to counter their salvos, it will take electronic warfare capabilities, it will take long-range precision strike.”