Why has Trump stepped in to prop up Japan’s currency?

The US has launched a bid to prop up the value of the yen, marking an extraordinary coordinated intervention with Japan’s government to halt the currency’s fall as it approaches 40-year lows.

Japan has been struggling to stop an accelerating slide in the yen, which has been piling pressure on its already flailing economy. Japan is reliant on imports for both energy supplies and food, and a weak yen makes the cost of those imports more expensive for businesses and consumers.