During his election campaign, South Korean president-elect Yoon Suk-yeol had tough words for his North Korean counterpart Kim Jong-un, saying he would teach his regional rival some manners and sternly deal with his provocative missile tests with a strengthened alliance with the United States.
But as he takes office on Tuesday for a single five-year term, the conservative Yoon must now confront an increasingly belligerent Kim, who openly threatens to use atomic bombs and is reportedly preparing for his first nuclear test in four years, part of an effort to build warheads that specifically target South Korea.
North Korea has a history of trying to rattle new governments in Seoul and Washington to gain leverage in future negotiations.
But if Kim orders a nuclear test, Yoon would be left with very limited options to deal with Kim at the start of his presidency.
There is scepticism among experts over whether Yoon, despite his rhetoric, can accomplish anything meaningfully different from outgoing president Moon Jae-in while North Korea continues to reject talks and focuses instead on expanding its nuclear and missile programs.
"North Korea has the initiative. Regardless of whether conservatives or liberals are in power in South Korea, North Korea is pressing ahead with (missile tests) under its own weapons development timetable before it tries to tip the balance later," Park Won Gon, a professor at Seoul's Ewha Womans University, said.
"North Korea will now continue its provocations, but there are no ways to stop it."
Moon championed engaging North Korea and once shuttled between Pyongyang and Washington to arrange now-stalled nuclear diplomacy.
Even after North Korea urged Moon not to meddle in its dealings with Washington and insulted him, Moon still worked to improve relations and shied away from hitting back at the North.
Yoon has described Moon's appeasement policy as "subservient" and accused him of undermining South Korea's seven-decade military alliance with the United States.
To neutralise North Korea's nuclear threats, Yoon said he would seek a stronger US security commitment and enhance South Korea's own missile strike capabilities - though he remains open to dialogue with the North.
During a rally before the March 9 election, as Yoon slammed Moon for failing to strongly criticise Kim's repeated missile tests, Yoon said that if elected, "I would teach (Kim) some manners and make him come to his senses completely".
Yoon has faced criticism that some of his policies are unrealistic and largely rehash past attempts that failed to persuade North Korea to denuclearise.
For example, Yoon said he would push for economic co-operation projects linked to progress in denuclearisation steps by the North.
Two past South Korean conservative presidents offered similar proposals from 2008 to 2017, but North Korea rejected the overtures.
Yoon said he would seek to establish a trilateral dialogue channel between Seoul, Pyongyang and Washington, but experts see little chance North Korea, which destroyed an unoccupied South Korean-built liaison office on its territory in 2020, will accept that idea.
"The US-South Korea alliance could flourish, but North Korea's nuclear weapons and missile program will further advance and that could elevate tensions on the Korean Peninsula to maximum levels," Yang Moo Jin, a professor at Seoul's University of North Korean Studies, said.
"It's hard to expect any meaningful progress in inter-Korean relations."
After this year test-launching a dozen missiles potentially capable of reaching the US mainland, South Korea or Japan, Kim recently said his nuclear weapons will not be confined to their primary mission of deterring war if his country's interests are threatened.
Recent satellite photos show North Korea is restoring a previously closed nuclear testing facility in possible preparation for its seventh atomic explosion.
Experts say that test is related to North Korea's push to manufacture warheads small enough to be mounted on tactical short-range missiles targeting South Korea, citing some of the North's recent tests of such weapons.
Kim seems to be trying to use his weapon tests to force the West to accept his country as a nuclear power so he can try to negotiate sanctions relief and security concessions from a position of strength.
Experts say Kim is able to push forward his weapons programs because the UN Security Council cannot impose new sanctions while its veto-wielding members are divided.
The US is involved in confrontations with Russia over its invasion of Ukraine and with China over their strategic rivalry.
Yoon's possible over-dependence on the US alliance may cause Seoul to further lose voice in international efforts to defuse the North Korean nuclear issue while giving Pyongyang less reason to engage in serious talks with Seoul, Lim Eul-chul, a professor at Kyungnam University's Institute for Far Eastern Studies in Seoul, said.
How to boost the South Korea-US alliance to better deal with North Korean nuclear advancement will likely top the agenda when Yoon meets US President Joe Biden in Seoul on May 21.