Russian President Vladimir Putin may use nuclear threats to deter a Ukrainian counteroffensive against the occupied Kherson, Zaporizhzhia, Donetsk, and Luhansk regions, according to a U.S.-based think tank.
The Institute for the Study of War (ISW) said in its July 19 war assessment that should the Kremlin annex the regions that are currently occupied by Russian forces, Putin may state, directly or obliquely, that Russian doctrine permitting the use of nuclear weapons to defend Russian territory applies to newly annexed territories.
Russia's military doctrine allows battlefield use of nuclear weapons in response to any non-nuclear assault on Russian territory. Versions of the doctrine published since 2000 state that Russia "reserves the right to use nuclear weapons to respond to all weapons of mass destruction attacks" on Russia and its allies.
"Such actions would threaten Ukraine and its partners with nuclear attack if Ukrainian counteroffensives to liberate Russian-occupied territory continue," the ISW said in its campaign assessment.
The think tank's assessment comes after top U.S. national security official John Kirby warned Tuesday that Russia is moving toward annexing areas in Ukraine that are currently occupied by Russian forces—a move that would mirror the annexation of Ukraine's Crimea peninsula by Russia in 2014.
"Russia is beginning to roll out a version of what you could call an annexation playbook," Kirby told a White House press briefing, citing newly declassified intelligence.
There is "ample evidence in the intelligence and in the public domain" to suggest that Russia plans to annex occupied Ukrainian territory, including Kherson, Zaporizhzhia, and all of the Donetsk and Luhansk regions, as soon as the fall of this year, Kirby said, pointing to Russian efforts to roll out the Russian ruble, install proxy officials, and force some residents to apply for Russian passports.
The deputy chairman of Russia's defense council, Dmitry Medvedev, said on Sunday there would be swift, tough action that would mean doomsday for Ukraine if Crimea is attacked.
The ISW said Putin may believe that the threat or use of nuclear weapons would restore Russian deterrence after his "disastrous invasion shattered Russia's conventional deterrent capabilities," adding that previous Russian hints at Moscow's willingness to use nuclear weapons have "proven hollow."
"Ukraine and its Western partners may have a narrowing window of opportunity to support a Ukrainian counteroffensive into occupied Ukrainian territory before the Kremlin annexes that territory," the think tank said.
The July 19 assessment also stated that the Kremlin is facing increasing pressure to declare a general mobilization. Declaring all-out war on Ukraine would allow Putin under Russian law to draft conscripts and mobilize reserve forces. Putin has so far described the ongoing conflict as a "special military operation" against Ukraine.
Newsweek has contacted Russia's Foreign Ministry for comment.
