Me thinking aloud again. Dangerous practice. But open to correction through comment. The first duty of any political entity's is to protect its citizens from external threat. This has been the case since cave dwellers began organising themselves into groups. Also the case that as the scale of threat has grown, it's been necessary to arrange defence on a scale capable of resisting attack from ever stronger forces. Terms such as 'Balance of Power' and 'Mutually Assured Destruction' have emerged within international politics to describe the consequences of this process. In today's world in practice, it means firstly that many countries in the West have merged military capability into one (more effective) unit, and secondly that the United States, vastly more rich and powerful than any other state has to be a part of it. Which brings us to NATO - our 'All for one;'One for all' defence policy.
But who pays. This is the question that has landed on Western leaders desks today. Donald Trump thinks the US is being required to do much of the heavy financial lifting. The accepted NATO target is that all countries should chip in 2% of GDP. The UK does. I think Poland does - two states which remember the horrors of 1939-45 better than most. Of all the statements/promises the incoming Commander-in-Chief has made over the last few months/years, the most worrying have been about his commitment to NATO.
With Rusia's President Putin on manoeuvres along Europe's Eastern borders, there will be much nervousness developing in EU capitals. I do hope the EU integrationists don't see Trump's words as a reason to divert resources to EU armed forces to fill a gap. Without the US, the EU will not have significant capability. Seems to me the best course of action is to start talking seriously to President Trump. It may even be that the UK will be well placed to broker sensible resolution. Now there's a though in our Brexit world. But at the heart of this, every EU state is going to have to get serious about defence. We will all have to our bit - a bit more I suspect.