The agreement between 12 countries to create the Trans-Pacific Partnership -- the world’s biggest-ever regional trading bloc -- and Korea’s exclusion from it poses a lot of challenges to the country.

First of all, the completion of the negotiations to form the mega trade bloc, which accounts for 40 percent of the world’s economic output, should reignite the debate not only on the timing of Korea’s entry but also on the country’s trade policy as a whole.

The 12 members in the largest regional trade and investment agreement in history account for a combined gross domestic product of $28 trillion, which is50 percent bigger than that of the European Union. Their combined trade volume stands at $11.8 trillion and their total population reaches 800 million.

The sheer size of the bloc’s economy is not the only important element. Led by the U.S. and Japan, the world’s No. 1 and No. 3 economies, and including some major Pacific Rim economies -- like Canada, Australia, Mexico, Vietnam, Chile and Singapore -- the TPP is certain to set the stage for establishing new rules and norms on global trade.

In fact, the TPP, unlike bilateral trade pacts, focuses on things like intellectual property, labor, the environment, state-run enterprises, services and investment. The U.S. Trade Representative summed up its value by saying that “TPP is a comprehensive agreement that will open markets, set high-standard trade rules, and address 21st-century issues in the global economy.”

One more thing that should not be overlooked is that the TPP will have considerable bearing on the region’s geopolitics, especially relations between the U.S. and China. U.S. President Barack Obama, who pushed for the regional trade pact as a centerpiece of his “Pivot to Asia” policy, did not hide what motivated the U.S., saying, “We can’t let countries like China write the rules of the global economy.”

Given the importance of the U.S. both as an economic partner and an ally, it was unwise of Korea to have been lukewarm toward the TPP initiated by Washington. Officials cite various reasons to justify their previous attitude: Korea had already concluded a free trade agreement with all but two of its 12 members -- Japan and Mexico. Besides, the Seoul government was preoccupied with a free trade pact with China, its largest trading partner.

Finance Minister Choi Kyung-hwan said that the government would scrutinize details of the TPP agreement and make a decision on when to Korea should join the pact. He also noted that Korea had already been in contact with relevant countries regarding the possibility of its participation in the bloc. Industry officials, including the Korea International Trade Association, are also pressing the government to join the TPP as soon as possible.

The best time for Korea’s participation could be before all the 12 members ratify the pact, which is expected next year or 2018 at the latest. It is against this backdrop that we hope President Park Geun-hye discusses this issue when she holds a summit with Obama next week.

All in all, the impending launch of the TPP tells us that the global trade regime will be more diversified and complicated. As the world’s seventh-largest trading power which thrives on an open economy, Korea must be armed with a trade policy befitting its status.