What would happen if Russia declared war on Nato?

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Western relations with Russia are at their worst since the height of the Cold War. The invasion of Ukraine continues towards the end of its third year and Vladimir Putin has made numerous threats towards Nato allies about direct further escalation.

Despite the Russian president saying "hardly anyone is interested" in being "one step away from a full-scale World War Three" if Russia goes into direct conflict with Nato, the Western allies are preparing for the worst-case scenario.

How would Russia wage war on Nato?

Though Nato is keeping the eventuality of "an all-out war" in its thinking, there is greater expectation that Russia will deploy "less obvious techniques designed to undermine stability in the alliance's member countries", said Newsweek. These could include a "limited incursion" into nearby states or "hybrid warfare tactics to probe the alliance's conviction".

This hybrid warfare could target "energy infrastructure, computer networks or transport systems: the nerves and arteries of modern society", and it takes place "in nominal peacetime" via "spies, soldiers and hired thugs", said Edward Lucas in The Times. This is already happening, and some Nato allies are "ready to respond decisively" while others do nothing, "fearing confrontation and escalation".

Labour cabinet minister Pat McFadden said last month that Russia is ready to launch cyberattacks on Nato. The "threat is real" and "no-one should underestimate" how "destabilising and debilitating" it could be, he said.

Is Nato ready for war?

In terms of ground warfare, Russia is "in no shape to take on Nato" as the Ukraine war rumbles on, said Al Jazeera. Despite a rapid expansion in troop numbers and assistance from North Korea to keep pace with the demands of the invasion, the Kremlin is not equipped currently for an all-out war without a pause.

Last week, Admiral Sir Tony Radakin, the UK's chief of the defence staff, said: "There is only a remote chance of a significant direct attack or invasion by Russia on the United Kingdom. And that is the same for the whole of Nato." Moscow, he added, "knows the response would be overwhelming, whether conventional or nuclear".

If Russia were to attack a Nato ally without time to replenish its military then Nato "would quickly prevail in any conventional war" given the quality of its troops "in terms of training and equipment", said Al Jazeera.

But things may not be that straightforward. The allies' "readiness for such a clash lies in doubt" after so many "underfunded" post-Cold War years, said Kyiv Independent. Nato can still "pack a punch" and while it will have the "upper hand" over Russia, it will suffer heavy losses and faces "ammunition shortages, a fragmented defence industry, and insufficient air defence coverage". Holding such a large alliance together for the "long haul" of a protracted war is a huge challenge for Nato and US President-elect Donald Trump has previously lambasted Nato allies who "do not meet the defence spending benchmark".

Many Nato countries, particularly those in the Baltics and bordering Ukraine, including Poland, are already pouring more money into defence, but "western Europe is lagging behind", said Newsweek. There are indications that France, Germany and the UK are already pushing towards a higher percentage of GDP spent on defence, but those in the east are encouraging more urgency.

What could trigger a war?

Nato would declare war on Russia if one of its members was attacked, triggering the alliance's Article 5 mutual defence clause. This could happen in the case of a ground invasion by Russian forces, though the head of German intelligence, Bruno Kahl, last month indicated that "Russia's acts of sabotage against western targets" could "eventually" push Nato to invoke Article 5, said The Guardian.

What could instigate a Russian declaration of war is unclear. Putin has made numerous threats and attempts to "draw red lines", which have been "repeatedly crossed" since the war began, said NBC News.

A full-scale declaration of war between Russia and Nato would be likely to pull in other countries and spread conflict. North Korea is already providing troops to Moscow in its Ukraine campaign, but a war with the West could see the "rise of a hostile axis", with China and Iran supporting Russia, said the Atlantic Council.