The US is widening what counts as tariff dodging, and that is bad news for Asian factories that rely on Chinese parts.

• Washington may soon look past where a product was finished and ask how much of it came from China.
• A White House report accuses more than 40 countries, including nine in Southeast Asia, of running a big rerouting scam.
• Companies that moved work to Vietnam or Malaysia to escape China tariffs are now under suspicion for doing exactly that.
• Customs paperwork is getting stricter, with imports possibly traced all the way back to raw materials.
• Trump has more tariff tools than before, including a 1930s law that lets him add up to 50% without asking Congress.

Outlook: Countries named in the report that also sell more to the US than they buy should expect more tariff pressure, and a Chinese-content "purity test" could reset the rules for the whole region.