Nuclear negotiations between the US and North Korea are at a standstill while the two countries show signs of changing attitudes.

When Kim Jong-un promised "complete denuclearization" last year, Washington and Seoul made some concessions to ensure he would keep his word. The two allied nations canceled an important annual joint exercise, sparking criticism from tough voices in the US such as John Bolton, a former White House national security adviser who once warned that the North's leader Tiên "is just playing".

The United States and South Korea have focused on diplomatic efforts to persuade North Korea to abandon its nuclear weapons program. Officials of the two countries put forward plans to help Kim realize the desire to revive the country's economy in exchange for Pyongyang's irreversible denuclearization. Some of the top diplomats in Seoul have described this unorthodox approach as a means of "bringing opportunity for peace".

But eight months after the second U.S.-North Korea summit closed to no avail, President Donald Trump's determination to resolve the nuclear crisis on the Korean peninsula through face-to-face dialogue dead. In addition, the North Korean leader has returned to the habit that has become his characteristic: Launching ballistic missiles.

Last month, Kim continued to exacerbate tensions with a new submarine-launched ballistic missile (SLBM) test, threatening the US mainland. Owning SLBM significantly increases North Korea's offensive capability, allowing them to retaliate against the nuclear even in the event that land-based missiles are destroyed. On the other hand, because the rocket operates under water, the United States is harder to detect.

The expert meeting between the United States and North Korea in Stockholm, Sweden, held shortly after the North's launch of the SLBM, also collapsed, further reducing expectations. Top North Korean negotiator Kim Myong-gil issued a warning about "horrific events" that could happen.

Facing North Korea's return to the old approach, the United States and South Korea are tending to favor a traditional stance on the Korean issue. The two countries are preparing to resume joint air defense exercises. The tone in Washington about North Korea gradually changes.

The Pentagon announced last week that the United States and South Korea will conduct joint air exercises in the Korean Peninsula next week. Stars and Stripes newspaper, US, quoted military officials as saying that the drills would replace the previous annual drills, Vigilant Ace, which was canceled last year along with Key Resolve and Ulchi drills. Freedom Guardian to promote talks with North Korea.

Pyongyang immediately resisted the decision from the US and South Korea. Kwon Jong-gun, the mobile ambassador of the North Korean Ministry of Foreign Affairs, called it a "reckless military frenzy" that risked pushing future nuclear talks to "brink of extinction".

"Our patience has reached the highest limit," Kwon said. "We will not sit still."

Signs of attitude change have begun to appear in Washington. Secretary of State Mike Pompeo last month implied that the United States might change its approach to North Korea.

"The truth is we can't rely on failed strategies to persuade President Kim to give up nuclear weapons," he said at the Heritage Foundation, a conservative research institute. "There is still a lot of work to be done."

Experts say that the warm external relationship between Trump and Kim actually did not lead to any progress in denuclearization efforts.

"The United States has tried several times to negotiate with North Korea, but Pyongyang has agreed to only eight days of diplomatic meetings over the past year and a half," said Bruce Klingner, a senior North East Asia researcher at the Asian Research Center. Á belongs to the Heritage Foundation, comment. "After the meeting in Stockholm, US officials presented new ideas but were quickly rejected by North Korea. Pyongyang instead reaffirmed the statement from Kim Jong-un that North Korea's patience. will be out by the end of the year, and warn they may continue to test nuclear and intercontinental ballistic missiles (ICBMs) ".

"Since the Singapore summit in 2018, Washington has loosened the old principles, canceled many exercises with allies and pampered a leader responsible for crimes against humanity," Klingner said. "Trump now accepts a weaker version of the 'strategic patience' policy that dates back to the Obama administration and is timidly enforcing sanctions."

Kristine Lee, an expert at the Asia-Pacific Security Program at the New American Security Center (CNAS), noted that Washington may be considering "adjusting" the policy to bring China into the picture.

Beijing and Moscow in July conducted their first joint air patrol in the Asia-Pacific region, showing their ambition to expand their political influence in the context of Washington's military commitment to the region. be skeptical.

"While US negotiators have focused on the task of dialogue with North Korea since President Trump and leader Kim Jong-un stepped into diplomatic paths in June 2018, China has just shown itself is a country struggling hard for peace and stability on the Korean peninsula and has taken advantage of its close relationship with Pyongyang to systematically undermine the American approach, "Lee said.

According to Chinese observers, Beijing will strongly oppose joint exercises between the US and South Korea.

Cheng Xiaohe, an associate professor at Peking University in Beijing, said the Chinese government will watch the exercise closely. But he also noted that Trump will find it difficult to change his current policy with North Korea due to domestic political instability.

"America's North Korea policy may be in turmoil for a while (because of the Trump impeachment investigation) but there is still good news that Trump himself wants to talk to North Korea, even though others (in the administration) ) does not want to, "Cheng said.

Harry Kazianis, director of defense research at the Washington-based National Interest Center, said Trump's prediction of foreign policy was "completely like a game".

"The US government is clearly facing a crisis when the deadline set by North Korea is about to come. In the coming weeks, I think Kim will conduct more modern missile tests to cause pressure on Washington, "Kazianis said. "Although the United States can pretend now that everything is okay with North Korea because it hasn't tested its nuclear or long-range missiles, I doubt Kim will break this commitment in the coming months. At that time, Trump will have to decide whether to continue to give in or return to the policy of maximum pressure. "