WASHINGTON — President Vladimir V. Putin’s calculated move on Wednesday 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, American 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.

William J. Burns, the C.I.A. director, said last week that “every day, 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, American officials have been more direct about the potential for an isolated Russian leader to lash out in further destabilizing 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 American 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 toward 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 continued, 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 as Russian forces seek to secure all of the Donbas region in the coming weeks. He has insisted to visitors like Mr. Nehammer that he remains determined to achieve his goals.

While Russian casualties have been high and Mr. Putin’s ambitions have narrowed in Ukraine, American 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, American 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 weapons 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, which 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 United States or its allies, the assumption has always been that Russia would make use of its cyberarsenal to retaliate for the effects of sanctions on the Russian economy. But eight weeks into the conflict, there have been no significant cyberattacks beyond the usual background noise of daily Russian cyberactivity in American networks, including ransomware attacks.

U.S. officials have been warning financial firms, utilities and others for six months to prepare themselves, and there is a growing body of evidence that U.S. Cyber Command and its equivalents in Britain and elsewhere have taken modest pre-emptive actions against the Russian intelligence agencies that are most active in cyberspace.

“If the Russians attack the West, NATO or the United States, that’s a fraught decision that has dire consequences on both sides,” Chris Inglis, the United States’ first national cyber director, said on Wednesday at an event hosted by the Council on Foreign Relations.

Mr. Inglis said that American government agencies and businesses had been provided ample “strategic warning” and were in a far better position to repel or recover from such attacks than they would have been a year ago.

But for all those threats, the American 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 what would lead the administration to back away from the ever-tightening pressure on Russia.

The administration’s public position is that none of the sanctions are permanent and that they were carefully crafted so they could be used at any moment as a source of leverage in a diplomatic resolution of the war. Presumably that would require Russia to pull all its forces out of Ukraine and cease hostilities in what Secretary of State Antony J. Blinken calls an “irreversible” way.

Right now, there is no prospect of that on the horizon. The attacks, one administration official noted recently, are more barbaric than ever and seem poised to escalate. But the effects of the sanctions seem likely to become harsher as well.

Speaking at the Georgia Institute of Technology last week, Mr. Burns, a former American ambassador to Moscow, said Mr. Putin was “an apostle of payback” who believes the West “took advantage of Russia’s moment of historical weakness in the 1990s.” He added that Mr. Putin’s small circle of advisers would hesitate to “question his judgment or his stubborn, almost mystical belief that his destiny is to restore Russia’s sphere of influence.”

That means getting the West to back away from Russia’s borders. And it means stopping NATO’s expansion, which may soon spread to Finland and Sweden, where a senior American defense official was visiting this week to discuss possible accession to the Western alliance.

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, though 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 antimissile defense,” 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. George F. Kennan, the architect of “containment strategy” — the effort to limit Soviet power — always warned that containment had its limits. “His concern,” said Michael Beschloss, a 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 Biden’s concern as well.