What happens when the world’s two biggest economies turn on each other

This could just be the beginning -- "the first of many" trade actions, as President Trump put it Thursday.

Trump announced plans Thursday to impose tariffs of 25% on $50 billion of Chinese exports. On Friday, Trump's global tariffs on steel and aluminum, which includes China, went into effect. Responding to those two latter tariffs, China said it would impose tariffs on $3 billion of US exports to China.

If it ends there, the skirmish is unlikely to have serious global implications. But the pain of higher costs and prices will be felt by workers, businesses and consumers, both directly and indirectly.