Donald Trump demanding allies hosting US troops cover full cost of deployment plus some extra

Donald Trump is demanding that allies with US troops stationed in their countries pay for the privilege in a concerted drive to bring down costs.

The US president wants such countries to not just cover the full cost of US troop deployment but also pay America an extra amount for the service.

Mr Trump upset negotiations with South Korea late last year by demanding “cost plus 50”, which means paying the full cost of deployment plus a further 50 per cent.

Does the US have to be deployed “everywhere?” Why should the US foot the bill?