On Thursday, President-elect Donald Trump tweeted that the “United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes.”

In the presidential debates, Trump said “Russia has been expanding” its nuclear weapons, adding that it has “a much newer capability than we do.”

But according to Jeffrey Lewis, the founding publisher of Arms Control Wonk, although Russia may have updated its missiles and warheads more recently, the idea that Moscow has better capabilities is “almost certainly not true.”

Kingston Reif, the Arms Control Association‘s director for disarmament and threat reduction policy, told Business Insider that the US’s nuclear arsenal is “second to none,” and that expanding US nuclear stockpiles risks “accelerating and worsening global nuclear competition and the chances of war.”

But fears that Russia has surpassed the US in nuclear ferocity are not completely unfounded. On paper, newer, more complicated, and more fearsome weapons constitute Russia’s nuclear arsenal.