Nevertheless, Park was conservative and her likely successor is liberal. The two opposing ideological camps pursue the country’s basic interests differently, with ramifications for South Korea’s role in the East Asia region.

Park’s liberal predecessors sought to reduce tensions with North Korea through engagement, economic cooperation, and reassurance that Seoul does not intend to invade and take over its northern neighbor. Park, however, was a hardliner on North Korea. She spoke openly about preparing for the collapse of the regime, condemned its human rights record, and finally closed the jointly operated Kaesong industrial park after Pyongyang’s fourth nuclear weapons test in January 2016. She approved deployment in South Korea of the Terminal High Altitude Area Defense (THAAD) anti-missile defense system, long urged by Washington but strongly opposed by China.

With Park out, the frontrunner to replace her is Moon Jae-in, leader of the liberal Minjoo Party. Moon would almost certainly adjust Seoul’s policies to be more accommodating toward North Korea and China and somewhat less acquiescent toward U.S. preferences.

This is an opportunity for North Korea, but one that pulls in two opposite directions. On one hand, for the next two months, control of South Korea’s armed forces is in the hands of an inexperienced interim president, 59-year-old Hwang Kyo-ahn, who was Park’s prime minister. Hwang is not battle-tested in making tough national decisions, and Pyongyang might calculate that he would hesitate to order a robust military retaliation against a limited, small-scale North Korean attack.

Pyongyang found occasional small attacks a useful part of its extortion strategy until 2010, when two lethal North Korean attacks moved Seoul to announce that another such attack would bring a disproportionate military response. If North Korean leader Kim Jong-un has been anxious to get in another punch without the certainty of a counter-punch, he might see this as a favorable time.

On the other hand, with a North Korea dove leading the candidates for South Korea’s next president, it would seem counterproductive for Kim to improve the political fortunes of South Korean conservatives by rattling nerves south of the demilitarized zone with another act of military intimidation before the election. Moon would likely steer South Korean policy back toward engaging North Korea, with more dialogue, unconditional economic aid, and a greater willingness to offer unilateral political concessions.

Moon has called for reopening Kaesong and removing some economic sanctions against North Korea, saying economic isolation has not stopped the North from pursuing its advanced weapons programs. The best way Pyongyang could help facilitate Moon’s election would be to stay out of the news for the next two months, although that will be difficult with the annual U.S.-South Korea military exercises, which Pyongyang considers highly provocative, underway and continuing into April.

South Koreans believe China, which buys about a quarter of South Korea’s exports, is crucial both to their prosperity and as a moderating force on Pyongyang. Park enjoyed a warm relationship with Chinese President Xi Jinping at the beginning of her tenure, but this gradually soured as China failed to rein in North Korea’s aggressive actions. The relationship then deteriorated abruptly as Seoul decided to deploy THAAD despite months of strident Chinese warnings.

THAAD’s ostensible purpose is to protect South Korea against North Korean missiles, but China contends that the system’s powerful radar could peer into China and thereby compromise its national security. In February, the South Korean corporation Lotte agreed to a land-swap with the South Korean government to provide the site for the THAAD base. In retaliation, 39 Lotte retail stores in China have been shut down by local inspectors, and Chinese authorities halted construction of one of Lotte’s large projects on the pretext of a failed fire safety check. China’s state-owned Global Times called for Chinese citizens to boycott South Korean cultural and entertainment imports, and the Chinese Communist Party’s People’s Daily newspaper said Beijing should consider cutting off diplomatic relations with South Korea.

Moon has been an opponent of THAAD, arguing that any benefit is outstripped by the program’s antagonism of the Chinese, making them less inclined to help Seoul manage North Korea. But with deployment already underway, THAAD will probably be in operation before the election, presenting the new president with a fait accompli. Moon is threading the needle on the issue. In a debate Tuesday, he said that while he wanted to resolve the dispute diplomatically, Beijing should “immediately stop” punishing South Korean companies in China over the issue.

Moon would likely seek to mollify China in some other way. That might give China increased leverage to block other forms of U.S.-South Korea security cooperation. Moon has said he supports the alliance with the U.S., but also believes Seoul should not agree to every American demand.

Solidarity on policy toward North Korea between Washington and Seoul has fluctuated over the years depending on the compatibility in outlooks between the particular leadership teams in office. Under Presidents Obama and Park, coordination was above average and the bilateral relationship was relatively smooth. It is uncertain whether this would continue with a liberal South Korean president such as Moon, given U.S. President Donald Trump’s pledge to put American interests first and Moon’s promise to defy Washington when necessary.

A key issue is whether the forthcoming Seoul government will continue to support Washington’s current position that no negotiations can take place with North Korea unless the Kim regime reaffirms its 2005 commitment to eliminating its nuclear weapons. Moon might favor opening negotiations without that precondition, which Washington would decry as rewarding Pyongyang’s bad behavior. That said, American policy toward North Korea might change also, as it is still under review by the Trump team.

The alliance will survive, but likely faces new strains even as Seoul comes under greater pressure from Beijing.

Denny Roy is a senior fellow at the East-West Center.