Why serious? Because Article 5 of the North Atlantic Treaty, the very bedrock of NATO’s existence and its fundamental raison d’etre, states: ‘The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.’Heady stuff. Article 5 has only been invoked once before, after the 9/11 terrorist attacks on the World Trade Center, and led directly to US and the West’s involvement in the wars in Afghanistan and, arguably, Iraq in 2003.But the true worth of Article 5 is not to the USA, but more to the other NATO allies, including the UK.Basically, it ties the USA, still the biggest strategic player on the planet, to the defence of Europe.That’s why everyone is scrambling to become a member in the face of perceived Russian military revanchism. For them NATO is the only game in town in terms of national security, hence the new found enthusiasm of Finland and Sweden, after decades of studied neutrality, to join.Part of the reason that Russia chose to invade Ukraine at the beginning of this year was to prevent the Ukrainians joining NATO.Russia has long been paranoid about being encircled by her enemies, and the accession of previous states of the former USSR to the western Alliance has exacerbated this fear. Russia has lost influence in its former vassal states and seeks to arrest, if not reverse, this trend.So, will Russia’s missiles hitting Poland elicit the full NATO Article 5 response? Putin better hope not, because if it does he’s on a losing wicket.NATO is infinitely stronger militarily than Russia is, especially after its losses in the Ukraine war, and a direct confrontation with NATO will most likely spell the end of the line for Putin and his acolytes.By all accounts Poland’s Prime Minister, Mateusz Morawiecki, has called for Poland’s Committee of the Council of Ministers for National Security and Defence Affairs to convene “as a matter of urgency”; the meeting will reportedly take place at 9pm local time (8pm UK time).However, let’s hope that wiser heads prevail and that an immediate response is tempered by common sense. It seems highly unlikely that this has been a deliberate attack against Poland by Russia and more a tragic mistake. Such things do happen in war, I’m afraid, because the waging of it is by no means a perfect science, or indeed art.To avoid a European conflagration, Russian must be profuse in its apologies for its stray missiles, and Poland magnanimous in its acceptance.All of this is, of course, small recompense for those families whose loved ones have been so cruelly and indiscriminately taken away from them.Lt Col Stuart Crawford