假设有朝一日美国通过关税和其他保护主义措施（包括特朗普所提出的重新谈判NAFTA和由墨西哥出钱修建边境墙）关闭与中国和墨西哥的贸易 — — 它们分别是贸易赤字第一大和第四大来源。
Presume for the moment that the US closes down trade with China and Mexico – the first and fourth largest components of the overall trade deficit – through a combination of tariffs and other protectionist measures (including the proposed renegotiation of NAFTA and a Mexican-funded border wall).