President Vladimir Putin’s Dangerous Moves

President Vladimir Putin of Russia has added new, chilling nuclear threats to his aggression in Ukraine, where 6,000 people have been killed in a war with Russian-backed separatists. Mr. Putin wants to expand his country’s influence and standing, but his alarming behavior has estranged Russia from most other major powers, damaged its economy and narrowed its future options.

Even for Mr. Putin, the recent nuclear threats have set a new benchmark for hostility in the conflict he has ignited with the West. Two weeks ago, The Times of London reported on a meeting between Russian generals and American officials in which the Russians threatened a “spectrum of responses from nuclear to non-military” if NATO moved more military forces into the Baltic States.

Last month, the Russian ambassador to Denmark, Mikhail Vanin, warned that Danish warships “will be targets for Russia’s nuclear weapons” if Denmark follows through on its expressed interest in joining NATO’s missile defense system.

Vladimir Putin Credit Mikhail Klimentyev/RIA Novosti

And in remarks aired on March 15, Mr. Putin said he was ready to bring nuclear weapons into a state of alert last year when Russia was in the process of invading and annexing Crimea. Some Russian officials have also hinted at the possibility of reintroducing nuclear weapons to Crimea, which has been free of them for two decades.

American officials say they have seen no evidence that Russia has actually begun to reposition or make ready a nuclear arsenal that still contains thousands of weapons. But even if the Russian threats are loose talk to intimidate adversaries or curry favor with nationalists at home, they reflect a cynical disregard for Russia’s post-Cold War role as a partner with America in arms control treaties designed to discourage the spread of nuclear weapons. These threats inevitably raise tensions and could increase the chances of deadly miscalculations.

Mr. Putin has crossed other lines, including sending military aircraft unannounced into international airspace over Estonia, Lithuania, Latvia, Poland and the North Sea. On April 7, a Russian fighter jet intercepted an American spy plane over the Baltic Sea north of Poland; the Pentagon complained the Russians acted in an “unsafe and unprofessional manner.”

There have been scores of similar episodes over the past year as NATO increased its air patrols in response to Russia’s invasion of Crimea.

The Russian leader’s decision to proceed with the long-delayed sale of an S-300 missile defense system to Iran was another bad choice. Experts say the system does not threaten Israel, which has nuclear weapons and the best military arsenal in the Middle East, but the move could make it harder for the Obama administration to get congressional support for a nuclear agreement with Iran.

Mr. Putin’s aggression is rooted in intense nationalism, which plays very well to his people and fuels the war against Ukraine. Despite a cease-fire agreement signed in Minsk in February, Russia has continued to arm, train and direct separatist rebels. Fighting has surged and there are grave concerns that Mr. Putin is planning an offensive to seize more territory in eastern Ukraine.

Russia’s bellicose behavior is a serious test for NATO, which has sometimes shown disturbing divisions. The Europeans and the United States have to stay united in maintaining sanctions on Russia and in continuing air patrols and training exercises, as it becomes increasingly difficult to predict Mr. Putin’s next move.