A market that can support fair trade, carbon-neutral, organic, and gluten-free markups can support a human-rights /value-subtracted/ tariff: goods produced by slave or child labor or under authoritarian regimes can be assessed a tariff to bring their prices in-line with those produced in better countries.

Stickers marked "Three children assembled this iPhone for you." or "These sneakers were stitched by slave laborers in Xinjiang" might be as effective as the USDA's "Certified Organic" in persuading those with money and a conscience.