At some point during the Trump administration, Russia told Defense Secretary Jim Mattis that it could use nuclear weapons in the event of a war in Europe — a warning that led Mattis to regard Moscow as major threat to the US.
According to “Fear,” Bob Woodward’s recently released book about turmoil in the White House, Moscow’s warning was in regard to a potential conflict in the Baltic countries of Estonia, Latvia, and Lithuania.
The Baltics were part of the Soviet Union and have deep ties to Russia, which has sought to reassert influence there since the end of the Cold War. Those countries have tried to move closer to the West, including NATO membership.
According to Woodward’s account, the warning from Russia came some time during or before summer 2017, when the Trump administration was haggling over the future of the Iran nuclear deal.
The size of Russia’s current stockpile of non-strategic nuclear weapons is not known, though it’s believed to be much smaller than that of the Soviet Union.
It’s not totally clear how Russia would use “tactical” nuclear weapons — the Congressional Research Service has said Russia appears to view them as defense in nature — but they are seen as compensating for Russia’s conventional military shortcomings. (US interest in “low-yield” nuclear weapons as a deterrent has also grown, though critics say they would raise the chance of US first-use.)
Russia has fewer “strategic” nuclear weapons than the US, and “tactical” nuclear weapons may be more handy for Moscow’s shorter-range, regional focus, Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, told The National Interest in late 2017.
“Russia’s conventional forces are incapable of defending Russian territory in a long war,” Kristensen said. “It would lose, and as a result of that, they have placed more emphasis on more usage of tactical nuclear weapons as a leveler.”