New York, United States - Originally billed as a low-profile talk on the military drawdown from Afghanistan, but amid fears of Russian aggression in Ukraine, this week's summit of NATO members has been elevated to one of the most crucial in the alliance's 65-year history.
Back in 1949, NATO's first secretary-general, Lord Ismay, said the alliance was forged "to keep the Russians out, the Americans in, and the Germans down". The collapse of the Soviet Union erased this common purpose; tensions over Ukraine have rekindled its necessity.
Ahead of the summit, US President Barack Obama plans to make a symbolic stopover in Estonia, a NATO member with a sizable Russian-speaking minority that fears Moscow-backed separatists in Ukraine are a prelude to a destabilisation in the Baltic.
Any potential aggressor knows that if they even started to think about attacking a NATO ally, they would meet not only national troops from that specific NATO ally - but they would meet NATO troops.
For Charles Kupchan, the White House's advisor on Europe, the message is simple: "Russia, don't even think about messing around in Estonia or in any of the Baltic areas in the same way that you have been messing around in Ukraine," he told reporters.
Estonia, Latvia and Lithuania joined NATO in 2004 and are protected under Article 5, the vow taken by every member that an attack on one represents an attack on all. Ukraine, where fighting between Kiev and pro-Russian separatists has claimed some 2,600 lives since April, has no such safeguard as a non-member.
The two-day summit in Wales beginning on Thursday aims to bolster NATO's military posture towards Russia while also mopping up its 12-year Afghanistan mission and checking the blitzkrieg advance of the Islamic State (IS) group in Iraq and Syria.
NATO's secretary-general, Anders Fogh Rasmussen, has revealed plans for a new unit of several thousand troops for Eastern Europe. Allies will supply troops on rotation for a "spearhead" brigade that can "travel light, but strike hard" and be deployed within 48 hours.
"Any potential aggressor knows that if they even started to think about attacking a NATO ally, they would meet not only national troops from that specific NATO ally - but they would meet NATO troops," Rasmussen told reporters on Monday.
A real threat?
Despite Rasmussen's hawkish words, analysts question the severity of the perceived Russian threat, and the commitment of some European members to boost military spending and hit Moscow with fresh sanctions.
Nick Witney, an analyst at the European Council on Foreign Relations, said Russia seeks only to maintain influence in Ukraine. President Vladimir Putin may meddle in the Arctic and the Balkans but is loath to challenge NATO in Poland or the Baltic.
"Even the Americans don't think there's a threat to NATO countries from Putin. That's why they're not getting dragged back into putting bases or a major infrastructure investment in central and Eastern Europe," he told Al Jazeera.
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"The halfway house is the symbolic step of thickening up deployments and exercises - enough to reassure the Europeans and deflect domestic critics in the US, but not a major investment in a threat that Americans don't really believe in."
NATO only acts by consensus and some key members are less combative on the Kremlin. Germans speak of "Russland verstehen", or understanding Moscow. France refuses to halt plans to sell Mistral helicopter carriers to Russia, with the first set for delivery next month.
Doves point to the 1997 Founding Act, which formally ended NATO-Russia hostilities and set rules for eastern European deployments. Washington complains that only four NATO members meet a 2006 commitment to spend two percent of national turnover on defence.
While Europeans cut military budgets amid economic crisis, Russia has become the third largest defence spender in the world. Washington's allies must "step up to the plate" and keep pace with new weapons systems, Kupchan said.
Ukraine's President Petro Poroshenko will attend the summit to secure NATO military support and push to join the US-dominated military alliance. Kiev said Russia shot down Malaysian Airlines flight MH17, which killed all 298 passengers and crew in July, and has ratcheted up military support for rebels by sending an invasion force onto Ukrainian soil. Russia denies the claims.
Kupchan said the "door is open" for Ukraine, but indicated that NATO leaders were more likely to agree on assistance packages to Georgia, another former Soviet republic, which fought a short war with Russia in August 2008, and the anticipated membership of Montenegro.
Russia's "hybrid warfare" tactics mark another difficulty for the alliance, he added. Deploying "little green men" without official Russian insignias prior to Crimea's annexation raises questions about whether stealth deployments across unchecked borders would kick-start an Article 5 response.
'A cancerous tumour'?
Putin likens NATO expansion to a "cancerous tumour." Boris Shmelyov, an academic with Russia's foreign ministry, said Ukrainian membership would impact Russia's security so badly that Moscow would have to deploy new weapons in its Baltic exclave, Kaliningrad.
Russia will do all in its forces not to allow Ukraine to be a member of the alliance.
"Russia will do all in its forces not to allow Ukraine to be a member of the alliance," Shmelyov told Al Jazeera. "In this situation, Russia will deploy missiles in the Kaliningrad region and other regions of Russia to keep the situation under control."
The Czarist-era term "Novorossiya", or "New Russia", has re-emerged in Moscow to describe the Black Sea region of Ukraine. Dmitry Babich, a political analyst with Russian state media, describes Russia and Ukraine as a historic "single organism". Ukrainian NATO membership would be "much worse than the situation in the 1940s, when the US had an atomic bomb and we didn't", he told Al Jazeera.
"The West is not prepared for an all-out war with Russia and will never take such a risk. Russia will have to reconsider its economic relations with the West," Babich said, warning of Moscow shutting gas pipelines to Europe in the frosty winter months.
The European Union and Washington have already slapped visa bans and asset freezes on Russian individuals and firms, and since July have ratcheted up sanctions by hitting the country's energy, finance and defence sectors.
But anything tougher than economic measures is unlikely. Washington has increased air patrols and deployed 600 paratroopers on training rotations in Estonia, Latvia, Lithuania and Poland, but President Obama said a "military solution to this problem is not going to be forthcoming" in Ukraine.
"Whilst I have great sympathy with the Ukrainians, I don't think the right way to deal with this crisis is to prepare to fight the Third World War - which is the road you embark down if you extend NATO military guarantees to Ukraine," Witney told Al Jazeera.
"Putin will not let go some grip on Ukraine and there's little we can do to stop him. His agenda is destabilising, which is a hell of a lot easier than stabilising. Unless we push this down to the wire and put an American, German and British division into Ukraine, then we have to look for a settlement."
While Ukraine's crisis tops the NATO agenda, US Secretary of State John Kerry said he will also use the summit to start the fight-back against the IS, which is also known as Islamic state of Iraq and Syria (ISIS) and has declared a caliphate across swathes of Iraq and Syria.
On Tuesday, the al-Qaeda offshoot released a video apparently showing the beheading of Steven Sotloff, 31, a US journalist held hostage by IS. Rights group Amnesty International accused IS fighters of "ethnic cleansing" of religious minorities in northern Iraq through mass killings, abductions and other war crimes.
The Pentagon has launched more than 123 airstrikes against IS targets. In a recent newspaper article, Kerry said he wants to "enlist the broadest possible assistance" to tackle the group, which includes Western passport-holders who are feared to be planning terror strikes in Europe and North America.
At the start of 2014, NATO still had to justify its existence. Fears of extremists in the Middle East and the icing of relations between East and West have solved that problem - and created others.
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