The article explores how governments switch between tariffs and non-tariff barriers in trade deals. When countries work together on tariffs, non-tariff barriers (NTBs) like quotas and antidumping rules become more common. As trade opens up, there’s a trend from tariffs to NTBs, changing which industries are affected. The type and extent of trade barriers used also depend on what each industry is like. The researchers observed that these findings match what happens in the real world.