News reports this week say that US lawmakers are urging trade action against China re its current exchange rate policy and other countries that pose barriers to access of US exports in their markets. These and potentially even bigger "shakes" in the world trade systemics and dynamics should not surprise those who have been reading my "food for thought" pieces on the unstable state of world trade systemics and globalization in general (on this blog or on Twitter) long enough.
IMO, no scenario is impossible as far as trade systemics are concerned, including WTO exit for US and EU (possible but not probable, yet IMO possible).
"Economic Fortress" USA and EU are not out of question IMO.
PS. The US has trade and investment barriers of its own, as well. But certain country/ies are masters in limiting market access (no need to mention name(s)).