President Donald Trump’s two-tiered trade deal with Vietnam aims squarely at practices China has long used to skirt US tariffs: The widespread legal shifting of production to Southeast Asian factories and the murkier and illegal “origin washing” of exports through their ports.

The Trump administration’s new trade deal with Vietnam aims to shut down any “backdoor” routes that allow Chinese goods to circumvent tariffs and flood the U.S. market. The deal, announced on Wednesday by President Donald Trump,