SEOUL, South Korea — Beyond a New Year’s declaration by North Korea’s leader, Kim Jong-un, that he would move to the mass-production of nuclear weapons and intercontinental missiles in 2018 lies a canny new strategy to initiate direct talks with South Korea in the hope of driving a wedge into its seven-decade alliance with the United States.
Mr. Kim, perhaps sensing the simmering tension between President Trump and President Moon Jae-in of South Korea, called for an urgent dialogue between the two Koreas before the opening of the Winter Olympics in the South next month.
The strained relationship between the allies has been playing out for months, as Mr. Moon, a liberal, argued for economic and diplomatic openings with the North, even as Mr. Trump has worked hard to squeeze the North with increasingly punishing sanctions. Mr. Moon also angered Mr. Trump and his aides in recent months by suggesting he holds what he called a veto over any American pre-emptive military action against the North’s nuclear program.
Until now Mr. Kim has largely ignored Mr. Moon, whom the North Korean media has portrayed as a spineless lackey of the United States. But the dramatic shift in tone and policy, toward bilateral talks between the two Koreas, suggests that Mr. Kim sees an opportunity to develop and accentuate the split between Mr. Moon and Mr. Trump, betting that the United States will be unable to mount greater pressure on the North if it does not have South Korean acquiescence.
The gambit may work. Hours after Mr. Kim’s speech, Mr. Moon’s office welcomed the North’s proposal, in a way that could further aggravate tensions with the United States.
“We have already expressed our willingness to engage in a dialogue with North Korea at any time, in any place and in any format, as long as both sides can discuss restoring their relations and peace on the Korean Peninsula,” said a presidential spokesman, Park Soo-hyun.
The statement emphasized the roles of the two Koreas in resolving the nuclear crisis. President Trump, in contrast, has pursued a tougher approach, saying there can be no talks without signs that the North is giving up its nuclear and missile testing, and without an understanding that the ultimate goal of any negotiations is a complete, verifiable dismantlement of the North’s nuclear capability.
“The timing of this overture, combined with his newly declared capability to strike the United States, is shifting the calculus,’’ said Robert Litwak, the author of “Preventing North Korea’s Nuclear Breakout,’’ and a scholar at the Woodrow Wilson Center for International Scholars. “Kim sees a rare chance here to take the side of the South Koreans, against President Trump.”
Mr. Kim may be partly motivated by an intense need to roll back sanctions that, by all accounts, have begun to bite.
As part of the overture, Mr. Kim also agreed to a request by Mr. Moon to send a North Korean delegation to the Winter Olympics. The South Korean president is betting that the North is far less likely to disrupt the Olympics, with missile launchings or an act of terrorism, if North Korean athletes are competing.
The diplomatic tug-of-war comes amid a backdrop of increasing fears over North Korea’s nuclear arsenal. Over the past year, the North made such fast technological advances that it says it can now strike the East Coast of the United States with a missile. The North has yet to demonstrate a key component of its nuclear threat — the ability to build a warhead that can withstand the heat and stresses of re-entering the atmosphere — but there is little dispute that it is getting much closer to such a capability.
The threat is considered strong enough by the administration that Mr. Trump has hinted at the possibility of a pre-emptive strike as a last resort.
That type of thinking — as well as fiery rhetoric from both Mr. Trump and Mr. Kim — has shaken South Korea, which would be expected to be on the front line of a war. The advances have also led the United States to push for tougher sanctions than before, and to close the types of loopholes Mr. Trump’s predecessors were more likely to overlook.
Despite the changes in the North’s nuclear capabilities, Mr. Kim’s New Year’s statement was similar to last year’s: The North’s nuclear program is unstoppable, and Mr. Trump should simply learn to accept it.
This time Mr. Kim described plans for “mass producing nuclear warheads and ballistic missiles for operational deployment” this year. While it is unclear what “mass producing’’ means in this context, American estimates of Mr. Kim’s arsenal range from 20 to 60 weapons; over the next few years that could easily double or triple, experts say, to an arsenal similar to Britain’s or France’s.
Those same officials, however, dismissed Mr. Kim’s comment that he now has a “nuclear button” on his desk as a rhetorical flourish. Currently, Mr. Kim cannot launch a weapon in seconds, as his declaration seemed intended to suggest. All of the tests he has conducted of intercontinental ballistic missiles have involved liquid-fuel weapons that take hours, sometimes days, to prepare for a launching.
The overture to the South came just days after Washington rallied its allies and rivals in the United Nations to support another round of tough sanctions against North Korea.
Even before that China had drastically cut back on direct shipments of oil and refined petroleum products that go through its pipeline to North Korea, American officials say, and there are reports of fuel shortages. Gas prices have more than doubled in the past year.
As Washington has campaigned for North Korea’s isolation, a number of nations — including Mexico, Peru, Kuwait, Myanmar, Spain, Italy and Germany — have recently expelled North Korean ambassadors or reduced the number of North Korean diplomats in their countries. And nations like the United Arab Emirates, Kuwait and Qatar have also begun phasing out North Korean workers toiling in construction sites there to earn badly needed cash for the North Korean government.
Mr. Moon officially supports the enforcement of United Nations sanctions as a tool to bring the North to nuclear disarmament talks. In recent weeks, his government has seized two oil tankers on the suspicion that they were used in violation of sanctions to smuggle refined petroleum products into North Korea through ship-to-ship transfers on the high seas.
But Mr. Moon also agrees with China and Russia that talks are needed to resolve the nuclear crisis. Mr. Kim’s sudden peace overture on Monday will probably encourage both Russia and China to renew their calls for some kind of “freeze for freeze” — a freeze on North Korean tests in return for a freeze on all American-South Korean military exercises. Presumably, under that situation sanctions would begin to ease.
“After getting nowhere with the Americans, North Korea is now trying to start talks with South Korea first and then use that as a channel to start dialogue with the United States,” said Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, who considered the North’s overture a positive development for easing tensions.
The big question now is whether Mr. Kim’s gamble will pay off. Hard-liners in South Korea, and some Trump administration officials, say they fear that if dialogue on the Korean Peninsula creates a temporary reprieve from tensions, the enforcement of sanctions could also be relaxed. Officials in the Moon administration argue that they are acutely aware of the North’s strategy and that they closely coordinate their moves with Washington.
Still, for Mr. Moon, talks between the Koreas would provide a badly needed respite after a year in which Mr. Kim and Mr. Trump regularly exchanged threats of war.
Increasingly anxious over a possible armed conflict, Mr. Moon seeks to create a lull in the nuclear standoff during the Olympics and use its momentum to start talks with North Korea. Such talks might eventually lead to broader negotiations in which the United States, China and Russia could offer economic and diplomatic incentives to the North in return for the freeze in testing.
And that is where the breach between South Korea and the United States could become a chasm.
In any future talks North Korea would be expected to seek major concessions, like the easing of sanctions and a reduction of the American military presence on the Korean Peninsula. The North would then probably try to force Washington to accept a compromise by offering to freeze its nuclear and missile tests, but not give up the weaponry. Or, as in the past, North Korea could use the talks to lessen the impact of sanctions without any intention of ending its nuclear program.
That would essentially freeze a status quo that Mr. Trump has declared is intolerable.