An introverted US means the world economy will contract, reduced production in China and Asia.
Looking forward to lower oil prices and overall lower market prices for manufactured goods.
On the flip side, innovation will slow down and with it slower improvement of productivity.
But!
Trump is a businessman so maybe nothing will really happen. He will soon discover that his rhetoric about being a tough negotiator works in business where the bottomline of profit and shareholders return does not apply to politics where peoples emotional needs transcends all. Then he will revert to status quo.
"The purpose of bureaucracy is to compensate for incompetence and lack of discipline." James Collins