A warning from @tylercowen:

If we tell companies they can't use supply chains that may have slave labor in them, "The losers will be U.S. consumers, who will face higher prices and less choice." 1/3 https://www.bloomberg.com/opinion/articles/2020-07-31/fight-slavery-with-boycotts-not-a-new-law-about-supply-chains

Notice how much further his argument goes than "don't worry about child labor, families only choose that if it's their best option." Now, even stripping outright slavery out of the supply chain is a mistake, because things will get even worse in countries that tolerate it. 2/3

But the proposal isn't to punish countries that have behaved badly, it's to give them a choice: either ensure no slavery or lose the supply chains. Maybe they'll do something about slavery. Incentives matter! This is not among the outcomes @tylercowen seems to contemplate. 3/3