Why a military response by alliance members is unlikely

NATO is highly unlikely to launch a military response to yesterday’s strike on Poland.

But the situation could become significantly more complicated if member states conclude that Moscow intended to hit a location where Western military supplies are stored.

Nato’s principle of collective defence, which is fundamental to the alliance, commits all members to take ‘such action as it deems necessary, including the use of armed force’, in the event of an ‘armed attack’ on any member.

The principle is enshrined in Article of the Washington Treaty and has been recognised since Nato was founded in 1949.

It dictates that armed force is an option in such a scenario but is not a response that members would be obliged to pursue. It would not be engaged if the missiles entered Poland by mistake.

Poland may instead turn to Article 4 of the treaty, which allows it to call on its fellow members to ‘consult together’ when its ‘territorial integrity, political independence or security’ is threatened.

It can then take action to restore security.