It occurs to me why Trump is such an advocate of encouraging other nations to pay for their own defence and it isn’t that America is “owed” money for “defending” other countries, it’s because America is broke. Stony broke. USA governments have put investment into military hardware above the well being of its citizens and now those citizens have some of the worst social care programs in the world which is well acknowledged. However a couple of points need to be borne in mind. The USA appointed itself the world’s policeman after WW2 and in so doing should bear the cost of doing so unilaterally. After being dragged into WW2 for the second time in 20 years America came to the conclusion that the two largest countries in Europe needed to be kept apart to avoid another world war. This is fair enough.
The second point is that after the collapse of the Soviet Union the purpose of NATO became obsolete, defunct, had no further purpose. When Trump declared this in his pre-election rallies, he was correct, still is.
However after Trump was elected and British PM Theresa May visited him to school him in the ways of the political system, he quickly changed his mind, saying he understood the importance of NATO. The point of Trump touring various countries on his first trip as US President, particularly NATO HQ and Brussels, is that he is asking other countries who seem to think that keeping NATO as an entity is a good thing and if this is the case they should pay for this.
What these countries don’t seem to understand is that NATO is an American entity and as such, comes under the command of the US. They are in effect being asked to fund further “wars on terror”. If these countries go along with this, they not only have blood on their hands right from the start, but they will end up like the USA, plundering the wealth of their nations for the sake of “security”. What’s more useful in keeping someone alive, a loaf of bread or a bomb? You can’t eat a bomb.