Opinion | Trump Is Reshaping the Nuclear Landscape

President Trump’s deference to Russia, his unprecedented rebuke of Volodymyr Zelensky and his no-holds-barred approach in prodding European partners to spend more on their military budgets are having an unintended impact among America’s longtime allies: a possible nuclear free-for-all.In recent days, emergency meetings have been convened in foreign capitals, and alarming public statements have been delivered by Poland, Germany and South Korea about their consideration of acquiring nuclear weapons.It’s a remarkable turn of events that portends a new nuclear landscape.America’s European and Asian allies haven’t contemplated their nuclear futures this earnestly — and openly — since the dawn of the atomic age.

For decades, they have relied on Washington’s policy of extended deterrence, which, by dint of treaties, promises more than 30 allies safety under America’s nuclear umbrella in exchange for forgoing the development of their own arsenals.The nations don’t need nuclear weapons to deter adversaries from a nuclear attack, according to the policy, because the United States guarantees to strike back on its allies’ behalf.But confidence in that longstanding arrangement began to break down after allies watched Mr.

Trump pull weapons and intelligence support from Ukraine last week in its war with Russia.It weakened further when he again upbraided NATO allies for not boosting their military spending, warning the other 31 alliance members not to count on the United States to defend them if they fail to meet their obligation to spend 2 percent or more of their gross domestic product on defense.Tremors from the president’s actions were promptly felt across the Atlantic.

Prime Minister Donald Tusk of Poland warned Friday about the “profound change of American geopolitics,” which put his country, and Ukraine, in an “objectively more difficult situation.” Poland must now consider reaching “for opportunities related to nuclear weapons,” he sa...