WASHINGTON (AP) — For two decades, Vladimir Putin has struck rivals as reckless, impulsive. But his behavior in ordering an invasion of Ukraine — and now putting Russia's nuclear forces on high alert — has some in the West questioning whether the Russian president has become dangerously unstable.

In recent days, Putin has rambled on television about Ukraine, repeated conspiracy theories about neo-Nazism and Western aggression, berated his own foreign intelligence chief on camera from the other side of a high-domed Kremlin hall where he sat alone. Now, with the West's sanctions threatening to cripple Russia's already hobbled economy, Putin has ordered  the higher state of readiness for nuclear weapons, blaming the sanctions and what he called "aggressive statements against our country."

The uncertainty over his thinking adds a wildcard to Russia's war on Ukraine. Western officials must confront Putin as they also wonder whether he comprehends or cares about cataclysmic consequences — or perhaps is intentionally preying on the long-held suspicions about him. 

An aide to French President Emmanuel Macron, who spoke with Putin on Monday, said the Russian leader answered Macron "without showing irritation, in a very clinical and a very determined manner."

"We can see that with President Putin's state of mind, there is a risk of escalation," added the aide, who spoke anonymously in line with the French presidency's practice on sensitive talks. "There is a risk of manipulation from President Putin to justify what is unjustifiable."

Foreign leaders have long tried to get inside Putin's head and have been wrong before. And Putin in this crisis is showing many of the same traits that he has displayed since becoming Russia's leader. Putin has directed invasions of neighbors, unspooled conspiracy theories and outright falsehoods, and ordered audacious operations like interfering in the past two U.S. presidential elections. 

He single-handedly made landmark decisions like the 2014 annexation of Ukraine's Crimean Peninsula, consulting only his narrow inner circle of KGB veterans and keeping everyone else in the dark. He has long been surrounded by lieutenants reluctant to risk their careers by urging caution, let alone voicing adverse opinions.

He has also talked about nuclear war and once mused that such a conflict would end in Russians going "to heaven as martyrs."

Experts say Putin could be using the specter of nuclear conflict to fracture the growing support for Ukraine's defense and to force concessions. His latest comments also suggest the sanctions are working. 

"We have to know this is a sign that we're getting to him," said Jim Townsend, a former deputy assistant secretary of defense and a senior fellow at the Center for a New American Security. "We just have to take that into account. We have to be cool."

Officials in the U.S. were alarmed by a 5,000-word essay published under Putin's name in July that argued Russians and Ukrainians are one people and blamed any divisions on foreign plots. One Biden administration official, speaking on condition of anonymity to discuss the U.S. government's internal thinking, said the intelligence community was concerned Putin was operating from "an emotional place" and driven by long-simmering grievances.

More recently, Macron went to meet with Putin and had several long phone calls before the invasion. A top official in Macron's office said last week that Putin was "no longer the same," had become "more stiff, more isolated," and at his core had veered into the approach now playing out.

During a five-hour dinner between the two leaders, Putin spent more time railing about NATO expansion and the 2014 revolution in Ukraine than discussing the immediate crisis. 

Putin's perceived self-insulation was highlighted in recent official meetings broadcast by state television. He faced foreign leaders and close aides from the opposite end of a long table. No Russian official who spoke gave a dissenting view. 

"He's not had that many people having direct inputs to him," said Sen. Mark Warner, a Virginia Democrat who chairs the Senate Intelligence Committee. "So we're concerned that this isolated individual (has) become a megalomaniac in terms of his notion of himself being the only historic figure that can rebuild old Russia or recreate the notion of the Soviet sphere."

Putin has long been committed to recovering lost glory, suppressing dissent and keeping neighbors in Moscow's orbit. In 2005, he called the collapse of the Soviet Union "the greatest geopolitical catastrophe of the century." Russia has fought a war with Georgia, annexed Ukraine's Crimea, backed separatists in eastern Ukraine, and earlier this year briefly deployed troops to help quell protests in Kazakhstan. 

His public dismissals of Ukrainian sovereignty go back many years. In 2008, he is reported to have told President George W. Bush, "George, you have to understand that Ukraine is not even a country." 

A year before that, he displayed his anger toward the U.S. and NATO in a pivotal speech at the Munich Security Conference, blasting the alliance's expansion eastward and attacking American military intervention abroad. The U.S. was mired at the time in the Iraq War, launched on the basis of false assertions about Iraq having nuclear weapons capability. 

"The United States has overstepped its national borders in every way," Putin said then. "This is visible in the economic, political, cultural and educational policies it imposes on other nations."

Rep. Chris Stewart, a Utah Republican who sits on the House Intelligence Committee, said he had not seen evidence prior to the Ukraine invasion to suggest Putin was behaving irrationally, and he noted that other world leaders in history have been dismissed by outsiders as irrational. Putin, he said, has "an incredible appetite for risk when it comes to Ukraine."

Two years ago, Putin endorsed the latest version of a Russian nuclear deterrent policy that allows for the use of atomic weapons in response to a nuclear attack or aggression involving conventional weapons that "threatens the very existence of the state."

Putin's associate Dmitry Medvedev, who served as placeholder president when Putin shifted into the prime minister's seat due to term limits, said in 2019 that a move by the West to cut Russia off from the SWIFT financial system would amount to an effective declaration of war — a signal that the Kremlin may view Western sanctions as a threat on par with military aggression. The sanctions announced in recent days include cutting key Russian banks out of SWIFT. The ruble has since plummeted. 

In 2018, Putin told an audience that Russia wouldn't strike first in a nuclear conflict but theorized about retaliating against an imminent enemy attack, adding with a smirk: "We would be victims of aggression and would get to heaven as martyrs. And they will just die and not even have time to repent."

James M. Acton, co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace, said he did not believe nuclear war was imminent but there was real potential for escalation. Another possibility was Putin would use increasingly brutal non-nuclear tactics in Ukraine.

Acton suggested finding an "off-ramp" that might allow Putin a perceived victory. In 1962, during the Cuban missile crisis, the U.S. secretly agreed to remove nuclear missiles from Turkey in exchange for the Soviets pulling back from Cuba. 

But, Acton added, "I'm not entirely clear whether he in his own mind knows what an off-ramp looks like right now."

Jeffrey Lewis, an expert on nuclear policy at the Middlebury Institute of International Studies, said he wasn't immediately worried about a nuclear escalation. But one danger of sending public signals about nuclear weapons is that they can be difficult to interpret, Lewis said, just as the world is trying now to understand Putin's latest moves and intentions. 

"He is isolated and making poor decisions and losing," Lewis said. "And that is dangerous."