U.S. President Donald Trump’s threat to slap new tariffs on trade partners the U.S. accuses of failing to crack down on forced labor will do little to fight modern slavery — and could even make things worse, experts, business groups and some human rights groups say. In its latest trade salvo, the Trump administration proposed additional duties of 10% or 12.5% on imports from 60 countries for failing to curb trade in goods made with forced labor, an assertion that U.S. trading partners rejected.