When Putin invaded Ukraine, he miscalculated the response from Western countries.
NATO has been largely united in its response to Russia's war, consistently providing Kyiv with military aid.
But some cracks have also emerged within the alliance.
The Ukraine war has brought NATO together in a way not seen in a long time, but it's also exposed cracks within the alliance as well.
NATO has, of course, had its problems in the past. A few years before Russia invaded Ukraine, for instance, French President Emmanuel Macron sharply criticized NATO, arguing the 63-year-old military alliance was experiencing "brain death" amid instability triggered by then-President Donald Trump.
But over the past 11 months since Russia launched its unprovoked assault on its neighbor, the alliance has largely shown itself to be strong, influential, and unified. NATO countries have provided billions of dollars in security assistance that has helped Ukraine defend itself, and the alliance even appears to be on the verge of expanding, one of Moscow's worst fears.
"A very unexpected consequence of this war has been the resurrection of NATO. My president was saying two years ago that NATO is brain dead. I think he was right at the time. It's not anymore the case, especially when you see that countries like Finland and Sweden, which were not members during the Cold War, have requested to join NATO," Gérard Araud, the former French ambassador to the US and the United Nations, told Insider.
Russian President Vladimir Putin has effectively succeeded in remaking the Western bloc, Araud said, adding that "the Western alliance is back." Things are far from perfect in NATO though, but they don't necessarily have to be for the alliance to do what it needs to do.
'Everything changed when Russia invaded Ukraine'
Throughout the Cold War, Finland and Sweden remained militarily non-aligned even as their Western neighbors were locked in a battle for ideological, technological, and military supremacy with the Soviet Union. After the Soviet Union collapsed, both Finland and Sweden became NATO partner countries but stopped short of pursuing full membership. Russia's invasion of Ukraine prompted a cataclysmic shift in thinking about European security, pushing Helsinki and Stockholm to abandon their historically neutral positions and apply for NATO membership.
"Everything changed when Russia invaded Ukraine," Finnish Prime Minister Sanna Marin said last April.
Finland shares an 830-mile border with Russia, and both countries would bolster the alliance with significant military capabilities. The vast majority of NATO countries have expressed enthusiasm for adding Sweden and Finland to the alliance, but enlarging the alliance requires approval from all current members and Turkey is standing in the way.
Turkish President Recep Tayyip Erdogan has accused the Nordic countries, particularly Sweden, of harboring Kurdish militants that Ankara considers terrorists and has urged them to crack down on these groups and speed up extraditions of suspected militants. In June, the three countries came to an agreement that appeared to alleviate Ankara's concerns.
But Erdogan has since continued to criticize both countries and demand more extraditions and expressed outrage over recent protests in Stockholm involving pro-Kurdish groups and Rasmus Paludan, a far-right, anti-Islam activist from Denmark. Turkey has ripped into Sweden for allowing the demonstrations, particularly given Paludan burned a copy of the Quran outside of the Turkish embassy. Swedish Foreign Minister Tobias Billstrom in a tweet condemned the Quran burning as "Islamophobic" and "appalling."
Sweden and Finland's NATO bids have been left up in the air. Turkey has indefinitely postponed talks with Finland and Sweden on their NATO membership bids that were set to be held in Brussels next month. Turkey's top diplomat, Mevlut Cavusoglu, said on Thursday that any dialogue at the moment would be "meaningless."
Some experts have suggested that Erdogan has moved to derail Finland and Sweden's NATO bids to distract voters from domestic issues, including major economic woes, ahead of Turkish presidential and legislative elections in May.
Erdogan, widely viewed as an autocrat, has frequently clashed with Western countries and NATO allies on an array of issues - especially over their support for the Kurdish-led Syrian Democratic Forces (SDF) in the fight against ISIS. In recent months, Erdogan has even made threats of war toward Greece, a fellow NATO ally. The Turkish leader has also faced criticism for his relatively amicable ties to Putin, and Turkey has not joined in on Western sanctions against Moscow over the Ukraine invasion.
Although Turkey has caused headaches for NATO, there's still widespread agreement that it's a vital member of the alliance.
"At some point soon, some NATO members are going to begin asking, 'If it is a choice between Sweden/Finland and Turkey, maybe we should look at our options.' That would be a mistake. Turkey boasts the second-largest army in NATO, has important facilities including Incirlik Air Base, and hosts NATO's overall land-warfare command in Izmir," former NATO Supreme Allied Commander Admiral James Stavridis wrote in a recent op-ed for Bloomberg.
Meanwhile, Hungary's opposition to sanctions against Moscow and refusal to back the supply of weapons to Kyiv - on top of democratic backsliding under Viktor Orban - has also caused headaches for NATO.
'There's always differences - fractures'
Beyond the troubles with Turkey, tensions recently emerged over Germany's sluggishness on sending much-sought-after Leopard 2 tanks to Ukraine. Berlin initially appeared reluctant to authorize the transfer of the German-made main battle tank to Kyiv, or even allow other countries to do so.
Growing impatient and recognizing Ukraine's pressing need for heavy modern tanks, scores of European officials began pushing Germany to green light the transfer, with Poland's top diplomat saying the "price of hesitation" is paid for in "Ukrainian blood." Warsaw even indicated at one point that it might go rogue and take matters into its own hands if Berlin didn't take action.
Germany finally gave the go-ahead on sending its tanks to Ukraine last week, a move that came in tandem with the Biden administration announcing it would send the formidable M1 Abrams tank to Kyiv.
"There's always differences - fractures that just come with being from different parts of Europe," Jim Townsend, the former deputy assistant secretary of defense for European and NATO Policy, told Insider.
"When they all sit down at a summit or somewhere like that, they're not breaking into fractions, and nations are leaving, and there's a food fight going on. They seem to work it out," Townsend said. "NATO functions by consensus. And so far, even with consensus being pretty strict, NATO has been able to take actions despite various countries individually having their own national view on what should be done and what should not be done."
Differences within NATO are nothing new and the disagreements of today really come down to how far NATO should go in standing up to the Kremlin's war in Ukraine, John Herbst, a former US ambassador to Ukraine and Uzbekistan, told Insider.
But even the hesitancy of some countries - like Germany and the US over the tank question - has been overcome by Russian atrocities in Ukraine, he noted. This is bolstered by strong urging from member countries in eastern Europe, in close proximity to Russia, and by hopeful future allies like Finland and Sweden.
"If anything, we've seen greater NATO unity as this has gone along," Herbst said. "The alliance has moved in the right direction on sending support to Ukraine," including the recent authorization to send Leopard and Abrams tanks.
Western Europe has realized 'Putin was, in fact, a menace'
Townsend said he is not surprised that NATO's unity has prevailed since the start of Russia's invasion nearly a year ago. Even under the intense pressure of war, the alliance is "holding the way that they have in the past," he said. NATO's foundation relies on its members having shared values when it comes to European and trans-Atlantic security, allowing it to operate effectively while ensuring the different viewpoints are part of the dialogue, he added.
Beyond NATO, this notion of unity can be observed within the European Union, too. The 27-nation bloc has been able to come together and provide both monetary and security assistance to Ukraine, while also braving the energy crisis that has plagued the continent. It has even accepted Ukraine as a candidate country, a historic move prompted by Russia's invasion that was seemingly off the table as recently as 2021.
Should this war go on for several more years, it's possible that NATO unity could be tested and undermined, Herbst said. For this reason, he believes the military alliance should be sending plenty of advanced weapons systems to make sure Ukraine expels Russia from all the occupied territory and make it difficult for Putin to retain the annexed Crimean peninsula.
It was only a few years before the Ukraine war that Macron delivered his "brain death" comment, and there were fears that Trump would try to pull the US from NATO if he won the 2020 presidential election. Former senior national security officials in the Trump administration even said at the time that such a move would be cheered on by Putin.
Herbst said he believes there's a greater recognition in Europe now that Putin's Russia is a "threat to our interests." Although this should have been noticeable years ago, he said, it took the invasion of Ukraine to "help persuade at least significant swaths of Western Europe that Putin was, in fact, a menace."