In the article, the researchers show how free trade agreements (FTAs) help countries reach global free trade more effectively than other trade systems. They set up a game where countries decide on trade strategies based on different trade setups. The study finds that FTAs make it easier to achieve global free trade because they help countries with different technology and demand levels reach agreements. Without FTAs, it’s harder for non-members to reject trade deals when there's a technology gap. FTAs also make it tougher to keep non-members out when there's a demand gap. The study suggests that FTAs can be a key tool in building global free trade and can work better than other trade setups.