Once the bigger, more systemically important countries start to discuss allowing trade discrimination and consider implementation of illegal practices, the damage could flow rapidly.  Now the bridge may face the largest challenge of all.  Donald Trump believes that other countries are getting more benefits than the Americans receive.  In his quest to remedy this situation, he and his team seem willing to overturn decades of policy. The assumption seems to be that the system itself will hold.  But the system rests on a shaky bridge.  The support piling represented by the United States is critically important to the overall structure.  If it gets knocked out, the entire bridge will start to fall.