President Putin was inaugurated this morning for a new six-year term. Setting a combative tone for the new Putin era, Russian troops in occupied Ukraine started training with battlefield or “tactical” nuclear weapons. The order went out yesterday for soldiers of  Russia’s Southern Military District to “practice the issues of preparation and use of non-strategic nuclear weapons.”

The Kremlin says the order was made in reaction to a string of hardline statements by Western “hotheads.” The British foreign secretary, David Cameron, broke a Western taboo and said Thursday at Kyiv that Ukraine could use British-supplied rockets to destroy targets inside Russia. That same day, the Economist posted an interview with President Macron, in which Monsieur Macron warned that, if Ukrainian lines fail, French soldiers could be sent to Ukraine.

Finally, on Sunday, the Biden Administration piled on in Washington. The minority leader in the House, Congressman Hakeem Jeffries, told CBS 60 Minutes: “We cannot allow Ukraine to fall. If this happens, there is a significant possibility that America will have to intervene in a conflict not only with our money, but also with our military personnel.”

On Monday, the Kremlin rattled its nuclear saber in the most threatening way since it embarked on its full scale invasion of Ukraine just over two years ago. Russia has 1,558 tactical nuclear warheads, according to the Bulletin of Atomic Scientists. Russia and America each are believed to have 1,600 active deployed strategic nuclear weapons — the kind designed to destroy a city.

In a war where Ukrainian troops are thinly spread out along a 600-mile front line, the battlefield utility of tactical nuclear weapons is seen as limited. However, wartime nuclear training means Mr. Putin’s new term starts with a rhetorical bang. America, Britain, Germany, and 19 other European Union countries boycotted Mr. Putin’s inauguration today.

Mr. Putin’s new term was designed to allow him to rule Russia for a span rivaling that of Stalin. This week, the Kremlin’s rhetoric is harsher than anything heard out of Moscow since the late Stalin era, the early 1950s.

“A devastating revenge strike” will be the reward for Washington and Brussels if Ukraine uses Western-supplied missiles to take out a Putin pet project, the 11-mile road and rail bridge connecting Russia’s mainland with Russia-occupied Crimea.

“The Crimean Bridge is once again in the crosshairs,” Russia’s Foreign Ministry spokeswoman, Maria Zakharova, told reporters in Moscow Friday. “Preparations for an attack on it, which is hard to believe, are now being carried out openly, with ostentatious bravado and with the absolute direct and shameless support of the collective West.”

The next day, the spokeswoman commented on NATO’s ongoing Steadfast Defender drills, the alliance’s largest exercise in Europe since the Cold War. She warned: “We have to admit that NATO is seriously preparing for a ‘potential conflict’ with us.”

In reaction to Lord Cameron’s green light to Kyiv to use British-supplied weapons to hit Russian targets, Britain’s Ambassador to Russia, Nigel Casey was summoned yesterday to the Russian Foreign Ministry. “Casey was warned that in response to Ukrainian attacks on Russian territory with British weapons, any British military facilities and equipment on the territory of Ukraine and abroad” could be targeted, the Russian foreign ministry said later. “The Ambassador was called upon to reflect on the inevitable catastrophic consequences of such hostile steps by London.”

Two weeks ago, after the American Congress approved $61 billion in largely military aid to Ukraine, a former Russian president,  Dmitry Medvedev expressed his wish on Telegram for America to be “plunged into a new civil war.” Responding to a portion of the aid bill that allows for confiscation of Russia state reserves in the United States, he proposed seizing private American assets in Russia.

Moscow’s angry rhetoric comes as the intelligence agencies of Britain, Germany, and other European nations report that Russia is planning sabotage attacks across Europe. “Assessments suggest Kremlin agents preparing covert bombings, arson and attacks on infrastructure,” is the headline of a story Sunday in the Financial Times.

Some attacks appear to have begun. Based on reporting from Berlin, London, and Oslo, the dispatch cited industrial arson in London, cyber attacks in Germany, physical attacks on journalists in Estonia, and attempts to sabotage Czech and Swedish railways. It said attacks were carried out “with little apparent concern about causing civilian fatalities.”

The Kremlin’s militant rhetoric matches the increasingly militarized nature of the new phase of Mr. Putin’s Russia. This year, more than one third of government spending is to go to defense — a post-Soviet record, calculates the  Stockholm International Peace Research Institute. In sync with the new trend, Ambassador-at-Large Grigory Mashkov told RIA news agency yesterday Russia should “build up the missile arsenal, in order to discourage any potential enemy from testing Russia’s strength.”

America, Europe, and China hope that cooler heads will prevail. In Washington, the White House national security spokesman John Kirby told reporters yesterday:  “It’s just reckless and irresponsible for a leader of a major nuclear armed power to be ‘saber rattling’ the way that he is with respect to potential use of nuclear weapons.”

In Paris, European leaders recalled that, six months into the conflict, President Xi Jinping in a joint press conference with Chancellor Scholz came out forcefully against Russia breaking the post-World War II moratorium on the use of nuclear bombs in a war. 

“President Xi has played an important role in de-escalating Russia’s irresponsible nuclear threats,” the EU commission president, Ursula von der Leyen, told reporters yesterday after meeting with Messrs. Xi and Macron. “I’m confident that President Xi will continue to do so against the backdrop of the ongoing nuclear threats by Russia.”

On Sunday, Le Figaro posted an essay by Mr. Xi, written to mark his first visit in five years to Europe. Writing last week, before the nuclear training order went out, the Chinese leader wrote of the Russia-Ukraine war: “I have stressed that nuclear weapons must not be used, and a nuclear war must not be fought.”