North Korea is poking holes through a global web of sanctions and generating enough cash to keep its nuclear weapons program moving along as a year-end deadline Kim Jong Un set to reach a deal with the U.S. approaches — with little progress in sight.

Instead of “concrete, verifiable steps toward denuclearization” — a mantra of President Donald Trump’s policy toward Pyongyang — Kim has yet to make any concessions on his nation’s nuclear program. The ability of the North Korean leader to find ways around United Nations sanctions is making it difficult for America’s “maximum pressure” campaign to deliver on what the Trump administration has promised.

“The problem is there is wiggle room, and while the sanctions are effective at squeezing the economy over the long run, I don’t believe Chairman Kim Jong Un sees them as a challenge in the short term,” Hugh Griffiths, who led the U.N.’s panel of experts on North Korea until earlier this year, said in an interview.

Kim has repeatedly threatened to find a “new way” if negotiations with the U.S. fail to progress by year-end, and recent talks in Stockholm lasted less than half a day. That timeline may reflect the American political calendar as much as Kim’s own. Trump could be hard-pressed to secure progress on North Korea while facing a possible impeachment and running for re-election.

Also making a year-end breakthrough less likely: The chief U.S. negotiator, Stephen Biegun, is Trump’s pick to be the No. 2 official at the State Department. While the formal nomination hasn’t been sent to the Senate, Biegun has largely been unable to meet his North Korean counterparts this year.

The result is a deadlock for diplomacy, which could be just what Kim wants. The U.S. is pushing hard to bring North Korea back to negotiations and South Korea was taking North Korea’s deadline “very seriously,” South Korean National Security Adviser Chung Eui-yong told reporters on Sunday.

“We have nothing to show for several years of diplomacy except for a far more capable North Korea and a less robust U.S.-South Korea relationship,” said Richard Haass, president of the Council on Foreign Relations. “He is uninterested in denuclearization. He’s interested in keeping nuclear weapons, keeping ballistic missiles and getting out from under sanctions. And it seems to me he’s making some progress.”

Underscoring the delicate state of U.S.-South Korea ties, Defense Secretary Mark Esper said Friday that Seoul needs to contribute more to host U.S. troops there. That followed Trump’s demands that South Korea pay about $5 billion to continue hosting U.S. troops, above the current level of about $1 billion per year.

“Korea is a wealthy country, and could and should pay more to offset the cost of defense,” Esper said at the start of an eight-day trip through Asia. He said he wants talks with Seoul finished by the end of the year.

North Korea has fired off at least 20 missiles in a dozen different military tests since breaking a testing freeze in May.