So far, the Ukrainian crisis is going very badly for Vladimir Putin.

Yes, the Russian president has arrayed roughly 100,000 troops on Ukrainexe2x80x99s borderxe2x80x94enough to mount a major invasion, if thatxe2x80x99s what he wants to do. But threatening Ukraine is only a means to Putinxe2x80x99s main strategic goals, which are a) to carve out a xe2x80x9csphere of influencexe2x80x9d that as much as possible recreates the old Russian (or Soviet) empire,xc2xa0 b) to deepen the politico-economic fissures within the European Union, and c) to drive a wedge between the United States and its NATO allies.

And yet his military gambit has accomplished the opposite. The overt threat to Ukraine has rallied the European nations around a common menace, revitalized NATOxe2x80x99s original mission to deter and contain Russian expansion, and thus bonded the European allies to the United States (the prime guarantor of their security) more tightly than any time since the end of the Cold War.

Putin had reason to believe things would go otherwise. He saw President Biden touting the Quadxe2x80x94the shiny new alliance of the U.S., Japan, India, and Australia, which would unify the Asian and Pacific allies and fend off a rising Chinaxe2x80x94and may have figured that NATO had receded in importance. He also watched Biden bug out of Afghanistan, and while he may have sympathized with the move (his beloved Soviet Union was among those entombed in that graveyard of empires), he no doubt noticed the withdrawalxe2x80x99s rushed incompetence and the concern, if not panic, that it roused among U.S. allies. Meanwhile, the UK was out on its post-Brexit own; Angela Merkel had retired as Germanyxe2x80x99s chancellor, leaving NATOxe2x80x99s largest, richest country in momentary flux; and French President Emmanuel Macron was seeking to take her place as the continentxe2x80x99s leader with a vision of Europexe2x80x99s xe2x80x9cstrategic autonomyxe2x80x9d from Washington.

Who knows whether all this was passing through Putinxe2x80x99s mind, but objectively it must have seemed a good time to make a movexe2x80x94especially since the pesky Ukrainian President, Volodymyr Zelensky, was drifting ever further to the west, renewing his request for NATO membership, and U.S. officials were indulging him, saying theyxe2x80x99d invite him in the club someday. Meanwhile, the U.S. was supplying Ukrainexe2x80x99s soldiers with weapons and sending American soldiers as trainers, along with corps of special forces and CIA agents, who were up to who knows what mischief.

From Putinxe2x80x99s viewpoint, the combination of threat and opportunity could only have seemed alluring. In 2014, hexe2x80x99d annexed Crimea and mounted armed incursions into eastern Ukrainexe2x80x94prompting some consequences (economic sanctions, expulsion from the G8, and other inconveniences) but nothing dreadful. Why should this time be any different?

So, starting in November (perhaps earlier), he moved dozens of tank battalions, rockets, infantry fighting vehicles, and tens of thousands of the troops to go with them, toward the border of Ukraine. We do not know whether he planned to invade or merely use the threat of an invasion to force concessions on his demands for NATOxe2x80x94to stop expanding its membership eastward and for the American military to roll back its presence in areas once held by the Soviet Union.

He may have figured that, even if Biden raised a fuss, the Europeans would be split. Some, including Germany, would be fearful of alienating Moscow, lest oil and gas supplies be cut off just as the winter temperatures were plunging. Certainly they wouldnxe2x80x99t risk hardship for the sake of Ukraine, which few Europeans wanted as a fellow NATO member and which most understood was of special importance to Russia.

In other words, Putin may well have expected resistance to fold before it mountedxe2x80x94compelling Zelensky to succumb to Moscowxe2x80x99s pressure without having to fire a shot.

But it didnxe2x80x99t turn out that way. Putinxe2x80x99s moves were too blunt, and his denials of any unusual activity were too blatant. Then came another surprising twist: Biden and his diplomats, who had made missteps in other realms, suddenly turned super-competent. Biden was comfortable with trans-Atlantic matters; NATO had been the centerpiece of U.S. foreign policy during his decades on the Senate Foreign Relations Committee and as vice president. Secretary of State Antony Blinken had been at his side, as top staffer, for many of those years. Deputy Secretary of State Wendy Sherman had eked results at the toughest negotiating tables. Their efforts held together the 30-state NATO alliance in opposing Moscowxe2x80x99s moves and threatening firm action in response to any further invasion of Ukrainexe2x80x99s territory.

Whatever Putin winds up doing, his plan of driving the NATO allies apart and reducing the U.S. presence near Russiaxe2x80x99s borders failed. In fact, Washington has put 8,500 more troops on high alert for deployment to Poland and Estonia, to shore up the eastern flanks of NATO. Poland and Britain have announced a xe2x80x9ctrilateral security pactxe2x80x9d with Ukraine, and, though no one knows quite what it means, the two countries are in the meantime redoubling their recent arms shipments to Kyiv. Sweden and Finland, Russiaxe2x80x99s thoroughly western neighbors, which have stayed militarily neutral for all these decades, are now mulling the prospect of joining NATO.

So what will Putin do now? The troops and tanks poised on the border are reportedly capable of overrunning the Ukrainian army, which, though much improved in recent years, would still be profoundly outmatched. But the Russian army has never been very good at maintaining supply lines. That would be a problem if they have to occupy a stretch of Ukrainian land, especially in cities. And they would be met not only by regular troops but civilian resistance fighters, whoxe2x80x94officials have warnedxe2x80x94will be aided by U.S. and NATO arms, logistics, and intelligence.

In Putinxe2x80x99s 22 years as either president or prime minister, his military moves have been cautious and limited. His annexation of Crimea was bloodless; not a shot was fired. (Most Crimeans viewed themselves as Russian anyway.) His incursion into eastern Ukraine was mainly to assist ethnic-Russian separatists; Kremlin officials continue to deny that Russian soldiers ever crossed the border, though an estimated 500 of them have died in the eight-year-old war. (More than 14,000 Ukrainians have died.) His invasion of Georgia took less than a week. The one time he sent ground forces to Syria, they were routed in an armed confrontation with U.S. troops; since then, he has assisted Bashir Assadxe2x80x99s regime almost entirely with air power.

If he did invade Ukraine, it would be not only the largest battle in Europexe2x80x94but also by far the most complex military operation Russia has undertaken anywherexe2x80x94since World War II. And the Russian boys returning home in body bags would have died not for the homeland, as they did fighting Nazis, but while trying conquer a neighboring country.

Finally, if the U.S. does impose the severe sanctions that Biden has consideredxe2x80x94including barring major banks and individual oligarchs from transactions in dollars, as well as banning the import of U.S. parts (which would gut Russiaxe2x80x99s high-tech industries)xe2x80x94the masses and elites may start growling at Putinxe2x80x99s xe2x80x9charebrained schemesxe2x80x9d (the epithet that the Kremlinxe2x80x99s commissars pronounced when they ousted Nikita Khrushchev for instigating the Cuban missile crisis, which ended in defeat and roused the U.S. to mount a crash buildup in nuclear arms).

Then again, if Russian tanks roll across the border, NATOxe2x80x99s much-touted unity may fall apart. If Putin responds to sanctions by cutting off oil and natural gas to Europe, Germanyxe2x80x94which is particularly dependent on Russia for energy suppliesxe2x80x94may fold. (It has already blocked Estonia from re-selling German arms to Ukraine and barred British planes carrying arms for Ukraine from flying across German airspace.) Many Russian oligarchs spend a lot of money on real estate in London; if they can no longer pay mortgages or property taxes, British businesses and Boris Johnsonxe2x80x94or whoever succeeds him as prime ministerxe2x80x94may lose patience as well.

Biden probably knows that broad expressions of unanimity tend to waver when blood starts to flow and money dries up, which is why he and the other Western leaders would prefer a diplomatic settlement as soon as possible. Nobody knows what Putin prefers. If hexe2x80x99s looking for an exit ramp off this highway to catastrophe, the question is how to get him to take it while giving him a way to save face. Simply backing him into a corner would probably push him to double down.

At his press conference on Tuesday with Hungarian Prime Minister Viktor Korban, Putinxe2x80x94who, until then, hadnxe2x80x99t spoken a word in public about the Ukraine crisis since Decemberxe2x80x94hinted at a possible way out. Mainly, he put on a pessimistic pose, complaining that Washington has ignored his main demand, a permanent ban on Ukrainexe2x80x99s entrance into NATO. (Korban assisted him by taking Putinxe2x80x99s side in the conflictxe2x80x94the first, utterly predictable NATO member to jump off the alliance bandwagon.)

However, Putin also made two remarks that mightxe2x80x94mightxe2x80x94shine a thin ray of hope on the gloomy landscape. First, he said that he had not yet responded to the letter Biden wrote last week in reply to Putinxe2x80x99s demands. In other words, diplomacy has not hit a dead end.

Second, he referred to (without mentioning their names) a few East-West agreements signed over the yearsxe2x80x94the 1975 Helsinki Final Act, the 1990 Charter of Paris, and the 1999 Istanbul Declarationxe2x80x94which U.S. officials have also referred to. The Americans have noted that these accords allow all countries to choose their own defense alliances, meaning that Russia has no right to dictate whether Ukraine can be a member of NATO. Putin noted that these same accords also say that no country can increase its security while threatening the security of others. Putin considers the further expansion of NATO, to include Ukraine, as a threat to Russian security.

One can imagine Biden acknowledging Putinxe2x80x99s point and calling for negotiations to begin on shaping 21^st-century European security in a way that protects the interests of all partiesxe2x80x94including Russia. As a first step, Biden could propose that Russia withdraw at least some of those troops and tanks from the Ukrainian border. In return, the U.S. might suspend military activities in Ukraine and, for the moment, elsewhere in Eastern Europe. Naval exercises in the Black Sea could also be halted while the talks go on. International inspectors could monitor all these movements and suspensions. Russians could inspect missile-defense sites in Eastern Europe, to verify that they cannot be used to support offensive missiles, as Russians say they believe.

The pointxe2x80x94the most that can be done for the momentxe2x80x94would be to de-escalate the tensions, make all military activities more transparent, and reduce the chance of miscalculations that could lead to war. And, at some juncture, Biden needs to find some way to assure Putinxe2x80x94sometime after thousands of tank turrets are no longer aimed at Ukrainian headsxe2x80x94that Ukraine is not going to join NATO any time soon. Itxe2x80x99s not going to happen for the foreseeable future; it shouldnxe2x80x99t be a cause of war.

Meanwhile, Putin is going to Beijing for the Olympics. He wonxe2x80x99t draw attention from the grand spectacle put on by Chinese President Xi Jinpingxe2x80x94who, as of late, has geopolitically speaking become his new best friendxe2x80x94by invading Ukraine. So for the next two weeks, war is very unlikely. Biden and NATO should use the opportunity to keep up the show of unity but turn down the heatxe2x80x94quietly prod Putinxe2x80x99s intentions by offering a path to a diplomatic solution. This venture may be playing out poorly for Putin so far, but if it escalates, it could become a disaster for everyone.