Economics (or political economy) has developed in major part as an effort to make clear various effects of trade policies.
[1] As China was rising in economic power and prominence, they turned to regionalism as a strategic method of leveling the playing field with Europe and the United States.
In 2000, China signed the Bangkok agreement with the Association of Southeast Asian Nations (ASEAN) to reduce tariffs in the region.
However, strained relations between China and other Asian nations such as Japan have prevented the same level of regional FTAs to be put in place with Northeast Asia.
[4] Relations between the European Union and South Korea have led to both parties signing several bilateral agreements regarding trade policy.
A common argument that has been made is that it allows businesses to open up markets that would otherwise be considered closed and therefore falls into the free trade idea that most countries will push for.
Countries that have similar levels of GDP and a higher scope in their economies as well as their relative position to one another and the rest of the world are more likely to have preferential trade agreements.
In modern history, generally starting at the mid-20th century, the use of tariffs has been largely diminished in favor of the rise of international trade.
[8] Beginning in 2017, the Trump administration began to impose tariffs on several of nations that were involved in trade deals with the United States.