The core principle of NATO’s international military alliance is a system of collective defence, meaning if any member state is attacked by a third party, every member state must step in to defend it.
Fortunately for countries such as Montenegro, which spent around $77m on defence last year, there are some military big hitters in the alliance. A NATO pledge asks members to spend 2% of gross domestic product on defence.
And though not all members reach this target, Stoltenberg has said it is “increasingly considered a floor, not a ceiling”.
The US spends more on defence than the next nine big spenders in the world combined. Its total in 2021 was estimated to be $801bn, according to Statista. In second place was China with estimated spending of $293bn, India with $76.6bn, the UK with $68.4bn and then Russia with $65.9bn.
As well as being the biggest defence spender in the world, the US has a powerful arsenal and a huge amount of manpower – with 1.39 million active troops, beaten only by India and China.
NATO data published last June showed that “while NATO defence expenditures are higher now than they were in 2014 (in total and as a share of GDP), the 2%-goal set by NATO in 2006 is still not reached in a slew of countries”, said Forbes.
The combined total of NATO military personnel currently exceeds 5.4 million – around four times as many as Russia, according to Statista. It has about five times as many aircraft, four times as many armoured vehicles and three times as many military ships. NATO and Russia have a similar number of nuclear warheads, both more than 6,000.
Research published in 2019 by the Royal United Services Institute (Rusi) found that assuming annihilation in a nuclear conflict was avoided, British forces would be “comprehensively outgunned” in a conflict with Russia in eastern Europe.
Rusi found that the British Army had a “critical shortage” of artillery and ammunition that would leave them struggling to maintain a credible defence position if Russia were to opt for all-out aggression.
“At present, there is a risk that the UK – unable to credibly fight – can be dominated lower down the escalation ladder by powers threatening escalation,” said Rusi’s report.
A former head of the institute, Professor Michael Clarke told Sky News in 2022 that current British and NATO rocket launcher systems were developed enough for combat, but that the allies would still “need much more” to hold off Russian forces with a long-range attack.
But the UK wouldn’t need to stand alone against Russia. And NATO’s biggest player, the US, has an overwhelming advantage over Russia in conventional forces.
Russian military analyst Felgenhauer told DW that open warfare often comes down to far more than the inventories that each side of the conflict can call upon.
“It’s like predicting the result of a soccer match: yes, basically, Brazil should beat America in soccer, but I have seen Americans beat Brazil in South Africa, at the Confederations Cup,” said Felgenhauer. “You never know the result until the game is played.”
Retired Air Vice Marshal Sean Bell told Sky News that another consideration was that Russia is not fighting by international rules of war. The Kremlin will do whatever it takes to win, without being bogged down by politics or the media, he argued.
“They’re not constantly looking over their shoulders about, ‘Oh, if we hit a civilian, if we hit a building…’,” said Bell. “They just get on with it.”