Nato's options if Putin strikes Polish airfield on front line

"Hybrid and cyber-attacks can trigger Article 5," Nato secretary-general Jens Stoltenberg said on Tuesday (11 October) in reaction, referring to Nato's mutual-defence pact.

Russian president Vladimir Putin has also threatened to strike at Western arms deliveries to Ukraine in the past and to defend annexed regions in eastern Ukraine with nuclear weapons.

One potential target is the military airfield in Rzeszów in eastern Poland, 50km from the Ukrainian border, where Western countries have been flying in arms for onward deliveries.

The US put Patriot air-defence systems there in March and Russian cruise missiles have already rained down in nearby western Ukraine.

If Russia struck Rzeszów "Nato, as per its doctrine, will respond in a proportionate measure," Luigi Binelli Mantelli, a retired naval admiral who was chief of defence staff in Italy from 2013 to 2015, told EUobserver.

"Nato will respond showing will and determination to discourage any further action from the opponent, while avoiding any damage that can lead to escalation. For instance, avoiding collateral damage," he said.

"In other words, it's a simple prediction of losses to be inflicted possibly equal to those which occurred due to the [Russian] first strike," Binelli Mantelli added, speaking in a personal capacity.

"Nato would have to decide how to retaliate, choosing from a suite of [conventional] options that Nato military commanders would propose," Jamie Shea, a former senior Nato official, also told this website.

"A full-scale Russian invasion of Nato territory would be different to a single missile strike as then Nato would be immediately engaged in repelling Russia back over its borders," he added.

Meanwhile, the risk Putin might use small-sized nuclear weapons to gain a battlefield advantage inside Ukraine was nil, said Pavel Baev, an expert on Russian security at the Peace Research Institute Oslo.

"It's quite impossible because Russian troops don't have protective gear and cannot possibly operate on a nuclear battlefield," he said.

Nuclear taboo

A "non-strategic" nuclear strike on Ukraine to cause terror and leave behind scorched earth in the event of a conventional Russian defeat "could be more feasible", he added.

But Russia had not placed warheads and delivery systems in place together with specially trained forces ready to pull the nuclear trigger, Baev said.

Any real preparations would be "absolutely detectable", he said. "The Russian ability to camouflage anything of significance in this war has been dismal," he added.

If the Russian leader did break the global nuclear taboo, which has held since 1945, Nato would also react with conventional strikes in a show of deterrent force, Shea and Baev said.

"I wouldn't rule out conventional military strikes by the US and its allies against a limited number of Russian targets, such as shipping or air bases, to warn Putin against further escalation," Shea, who now teaches war studies at University of Exeter in the UK, said.

"As long as Nato territory is not attacked with nuclear weapons, I would rule out a Western nuclear response," he said.

Nato would likely "target very precise [Russian] military assets, minimising 'collateral damage'," Baev said. "Naval platforms are one such option, the [Russian] bases in Syria — another one, the bases in the Arctic — yet another," he added.

"For Nato, the key message is that a first Russian use (even if testing) would be answered by conventional means — and with devastating efficiency," he said.

Other Western measures might include deliveries of the US' "most long-range weapons" to Ukraine, Shea said, "so that Kyiv can retaliate appropriately in a way that will exact a high price on the Russian military".

They might also include a Western blockade of Russia's Kaliningrad exclave in the Baltic Sea, Baev said.

Putin's logic

For his part, Binelli Mantelli voiced scepticism on nuclear escalation.

"I don't think Putin is so naive as to use nuclear weapons, because he cannot be totally defeated in his [conventional] campaign. Russia can sustain its efforts for a long time, longer than we can imagine," he said.

Putin's best option would be to cede most of the conquered territories in return for guarantees Ukraine would never join Nato, the Italian admiral added, in what the Kremlin could still present as a victory.

But for Shea, the political logic of Putin's position was becoming more "dangerous" for the West with each war crime in Ukraine.

"Putin has already lost any opportunity to appear as a peacemaker given the brutal tactics he has used and the mounting charge sheet of war crimes that will be laid at the door of his regime and Putin personally," Shea said.

"If Putin backs down from his threat to use nuclear weapons this will be seen as the success of US and Nato," Shea added.

"His bluff will have been called and he will be weakened politically inside Russia," Shea said.