(Bloomberg) -- The last time a US president visited Seoul in 2019, Donald Trump and Kim Jong Un agreed to restart nuclear talks during an impromptu meeting at the heavily fortified demilitarized zone. 

As Joe Biden prepares to land in Seoul on Friday, the White House hasn’t indicate he’ll be heading to the DMZ. There’s also little he can do to convince Kim to return to the negotiating table as the North Korean leader prepares to launch another intercontinental ballistic missile and possibly conduct his first nuclear test since 2017.

The U.S. push to isolate Russia over Vladimir Putin’s war in Ukraine, coupled with increasing animosity toward China, has allowed Kim to strengthen his nuclear deterrent without fear of facing more sanctions at the UN Security Council. There’s little chance Russia or China would support any measures against North Korea, as they did in 2017 following a series of weapons tests that prompted Trump to warn of “fire and fury.” 

Although North Korea remains poor, and is facing its first widespread Covid-19 outbreak, the nation has shown it can survive under the current set of economic penalties and won’t come running for sanctions relief, according to Kang Mi-jin, a North Korean defector who now runs a company in South Korea that watches the economy of her former home.

“There’s zero incentive for Kim Jong Un to return to high-stakes nuclear negotiations in return for economic incentives,” she said. “Nuclear weapons have now became an essential tool for the survival of Kim’s regime survival. It’s not a bargaining chip for economic sweeteners.”

The White House has largely avoided stern reactions to Kim’s latest tests, including an ICBM launch on March 24. New South Korean President Yoon Suk Yeol has also offered an “audacious” package of aid for nuclear disarmament. 

Sung Kim, the US special envoy for North Korea, last month said the administration hasn’t received any response from North Korea to repeated invitations for a dialogue without preconditions.

“We hope that the North Koreans will accept our invitation to engage in a serious and sustained dialogue,” Sung Kim said. “We are willing and prepared to address any serious concerns that they may have about their situation on the peninsula.”

Kim has been wary of any deal that would see him give up his nuclear weapons, particularly after Libyan dictator Moammar Qaddafi was killed at the hands of U.S.-backed rebels after giving up his weapons of mass destruction in exchange for an easing of sanctions in 2003.

The threat from North Korea was far less when it reached its two major nuclear deals. A 1994 agreement to halt its nuclear program in exchange for a proliferation-resistant light water reactor came when North Korea relied on Soviet-knockoff Scud missiles and barely had enough fissile material for a bomb test. The second one came about a dozen years later, when the regime was offered heavy fuel oil now valued at about $665 million in return for shutting its Yongbyon nuclear plant, which churned out enough plutonium for about a single bomb a year. 

Now North Korea’s nuclear program is far more expansive. Experts estimate it can produce enough fissile material for six to eight nuclear bombs a year. Its missile program includes an array of rockets that are quick to deploy, maneuverable in the air and can reach the U.S. mainland. 

Even if North Korea surrendered what it has now, the country would still maintain the expertise to rebuild parts of its program. 

“Most people who watch North Korea agree that the chances of a negotiated settlement are approximately zero,” said Stephan Haggard, a professor of Korea-Pacific Studies at UC San Diego and a specialist on North Korea’s economy. “For alliance management purposes and to maintain the high ground, the US and South Korea have little choice but to continue to make the offer of talks.” 

Kim has also found ways to evade sanctions through cybercrimes and crypotcurrency theft. Investigators from the U.S. and United Nations have said his regime has already taken in nearly $3 billion  -- or about 10% of its annual economy -- through cybercrimes, and is poised to rake in even more.

The sanctions regime has shown cracks in items such as oil imports. A UN Security Council Panel of Experts report from earlier this year said North Korea had exceeded its 500,000 barrel cap of annual imports by about 25,000 barrels. In addition, an oil pipeline between Dandong in China and Sinuiju in North Korea stayed open despite the sanctions and could be supplying more than 500,000 tons (3.7 million barrels) of oil annually, according to a report from specialists David von Hippel and Peter Hayes. 

Russia’s invasion of Ukraine also helps North Korea, von Hippel, a senior associate for energy and environment issues at the Nautilus Institute, said in an email.

“The war in Ukraine will make is somewhat easier for the DPRK to import oil products and export coal to get around sanctions,” he said, referring to North Korea by its formal name.

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