The Yomiuri Shimbun
This is the third and final instalment in a series
"North Korea has never been left unattended to, not for one day," said US Secretary of State John Kerry at a press briefing in Washington on Thursday.
Washington has faced criticism that it spent so much time dealing with Iran's nuclear development and other issues that it failed to make enough effort to deal with the North Korean problem. The administration of US President Barack Obama felt increasing irritation as this criticism grew louder.
However, it cannot be said the Obama administration has proactively engaged in North Korean issues in recent years.
Upon its inauguration in 2009, the administration initially presented a policy of pursuing solutions through direct dialogue with North Korea. In February 2012, the United States and North Korea agreed that Pyongyang would discontinue uranium enrichment and other related activities at its Yongbyon site.
Despite those US diplomatic actions seeming to have borne fruit, North Korea test-fired a long-range ballistic missile about 1½ months later and the agreement was scrapped.
Betrayed by Pyongyang, the Obama administration switched over to the "strategic patience" policy under which the US government does not hold dialogue with North Korea unless Pyongyang takes practical actions for terminating its nuclear development. The Obama administration closed the door to dialogue with Pyongyang.
Scott Snyder, a senior fellow of the Council on Foreign Relations, a US policy think tank, said the strategic patience policy lacked tension. The policy resulted in giving North Korea time for its nuclear development without positive effects for the United States.
The situation enabled North Korea to conduct a nuclear bomb experiment for the third time since the Obama administration was inaugurated.
Josh Earnest, the press secretary for the US president, admitted the allegation.
On Wednesday, he said it was true that the US government has not achieved its goal of denuclearizing North Korea.
In the United States, an increasing number of people have urged the US government to commit more to North Korea. However, it is hard to say the Obama administration's own economic sanctions on North Korea have been effective.
Experts assume that economic sanctions will not cause as much damage to North Korea, which has been isolated internationally, as they do for Iran - a major power in the Middle East with abundant natural resources.
Snyder clearly said that since most of North Korea's trade partners are Chinese companies, co-operation from Chinese authorities is essential for effective economic sanctions.
However, Beijing is also irritated by the North Korean issue since China has been forced to stand on the front line regarding sanctions.
A spokesperson of the Chinese Foreign Ministry voiced antipathy, saying, "The origin of, nor the key to solving, the nuclear problem does not exist in China."
Beijing has taken an insistent tone that all relevant countries should bear joint responsibility for stopping North Korea's nuclear development.
Pyongyang neglected the advice of the administration of Chinese President Xi Jinping when conducting its latest nuclear test and failed to provide advance notice.
The Chinese government said it has not confirmed whether the test was a hydrogen bomb.
However, the progress of North Korea's nuclear development will lead to what Beijing is most wary of - a reinforcement in security co-operation between Japan, the United States and South Korea.
It is highly possible the Xi administration will impose pressure on North Korea and take a more hard-line stance.
In fact, the Xi administration faces criticism not only from the international community but also from within China.
On Chinese websites, there are many postings condemning North Korea partly because of fears of pollution from radioactive substances.
Some have accused the Chinese government, with one saying it "has continued to give aid to a mad dog of the Kim family and has exposed us to contamination." It seems the "mad dog" it refers to is North Korean leader Kim Jong Un.
Despite the harsh response, the Chinese government is in a dilemma whereby it cannot toughen sanctions against North Korea to a degree that would endanger its regime. Beijing fears a chaotic situation might occur around the border between the two countries.
While experts have pointed to a stagnation in foreign affairs, including US-China relations, a diplomatic source in Beijing said China "cannot totally give up North Korea as it is still useful as a bargaining chip."
According to The New York Times, the US government has started making a draft resolution that will toughen existing sanctions and which the UN Security Council aims to adopt.
Will the United States be able to win consent from China and make a sanction resolution viable? In New York, a place far from the Korean Peninsula, tight-rope wheeling and dealing is continuing. Speech