WASHINGTON (NYTIMES) - Russian President Vladimir Putin's calculated move on Wednesday (April 20) to test launch a new intercontinental ballistic missile, declaring it a warning to those in the West who "try to threaten our country", fed into a growing concern inside the Biden administration: that Russia is now so isolated from the rest of the world that Mr Putin sees little downside to provocative actions.

Even before the missile launch, United States officials and foreign leaders were weighing whether their success in cutting Russia off from much of the global economy, making it a diplomatic pariah, could further fuel Mr Putin's willingness to assert his country's strength.

The first launch of the nuclear-capable Sarmat missile was just the latest example of how he has tried to remind the world of his capabilities - in space, in cyberspace and along the coast of Europe - despite early setbacks on the ground in Ukraine.

"He is now in his own war logic," Chancellor Karl Nehammer of Austria said last week after meeting Mr Putin in Russia. He described the Russian president as more determined than ever to counter what he sees as a growing threat from the West and to recapture Russia's sphere of influence in Eastern Europe.

The US Central Intelligence Agency's director William Burns said last week that "every day, Mr Putin demonstrates that declining powers can be at least as disruptive as rising ones", adding that his "risk appetite has grown as his grip on Russia has tightened".

In private, US officials have been more direct about the potential for an isolated Russian leader to lash out in further destabilising ways.

"We have been so successful in disconnecting Putin from the global system that he has even more incentive to disrupt it beyond Ukraine," one senior intelligence official said in a recent conversation, insisting on anonymity to discuss intelligence assessments. "And if he grows increasingly desperate, he may try things that don't seem rational."

Mr Putin, assessments delivered to the White House have concluded, believes he is winning, according to a senior US official who asked for anonymity to discuss intelligence findings.

He is certainly acting that way.

It is hardly surprising that Mr Putin has not backed down in the face of economic sanctions and measures to cut off his country from technology needed for new weapons and now some consumer goods. He has often shrugged off Western sanctions, arguing he can easily manage around them.

"We can already confidently say that this policy towards Russia has failed," Mr Putin said on Monday. "The strategy of an economic blitzkrieg has failed."

He was immediately contradicted by his own central bank chief Elvira Nabiullina.

"At the moment, perhaps this problem is not yet so strongly felt, because there are still reserves in the economy," she said. "But we see that sanctions are being tightened almost every day," she said, adding that "the period during which the economy can live on reserves is finite".

But that reality apparently has not sunk in. If anything, Mr Putin has grown more belligerent, focusing new fire on Mariupol, Ukraine, as Russian forces seek to secure all of the Donbas region in the coming weeks. He has insisted to visitors such as Chancellor Nehammer that he remains determined to achieve his goals.

While Russian casualties have been high and Mr Putin's ambitions have narrowed in Ukraine, US intelligence assessments have concluded that the Russian president believes that the West's efforts to punish him and contain Russia's power will crack over time.

With the help of China, India and other nations in Asia, he appears to believe he can avoid true isolation, just as he did after the annexation of Crimea in 2014.

Now, US officials are girding for what increasingly feels like a long, grinding confrontation, and they have encountered repeated reminders by Mr Putin that the world is messing with a nuclear power and should tread carefully.

On Wednesday, after providing warnings to the Pentagon that a missile test was coming - a requirement of the New START treaty - a nuclear arms reduction treaty between the US and Russia and has four years remaining - Mr Putin declared that the launch should "provide food for thought for those who, in the heat of frenzied aggressive rhetoric, try to threaten our country".

In fact, the missile, if deployed, would add only marginally to Russia's capabilities.

But the launch was about timing and symbolism: It came amid the recent public warnings, including by Mr Burns, that there was a small but growing chance that Mr Putin might turn to chemical weapons attacks or even a demonstration nuclear detonation.

If Mr Putin turns his sights on the US or its allies, the assumption has always been that Russia would make use of its cyber arsenal to retaliate for the effects of sanctions on the Russian economy.

But eight weeks into the conflict, there have been no significant cyber attacks beyond the usual background noise of daily Russian cyber activity in US networks, including ransomware attacks.

But for all those threats, the US position has been to keep amping up the pressure on Mr Putin - from sanctions to diplomatic isolation to the provision of more powerful weapons to the Ukrainian military.

"Ukraine already won the battle for Kyiv," one administration official said. He added that the administration would "continue to provide Ukraine with an enormous amount of arms, training and intel" so that it "could keep winning".

It is far from clear that the Ukrainians will keep winning now that the fight has moved away from the urban streets of Kyiv, to more familiar, flatter ground in the Donbas.

Nor is it clear what exactly would lead the administration to back away from the ever-tightening pressure on Russia.

At the beginning of the Ukraine war, Mr Putin publicly ordered his nuclear forces on higher alert status as a signal of Russia's power, although Mr Burns has said there is no evidence that the forces actually went on heightened alert.

The test on Wednesday of the Sarmat missile, in development for years, was another mixed signal. While Mr Putin described it as "capable of overcoming all modern means of anti-missile defence", arms experts say that is hyperbole. But the hyperbole fits into a pattern.

Historians of the Cold War point out that little of this is new.

The late American diplomat and historian George Kennan, the architect of "containment strategy" - the effort to limit Soviet power - always warned that containment had its limits.

"His concern," said Mr Michael Beschloss, a US presidential historian who has written extensively about that era, was that "if they become a pariah nation, you don't have very much influence on them".

Over the next few months, that may become President Joe Biden's concern as well.