South Korea's dovish new President Moon Jae-In -- who backs engagement with the nuclear-armed North -- heads to Washington this week for talks with his hawkish US counterpart Donald Trump, as Pyongyang defies international sanctions to accelerate its missile programme.
Centre-left Moon suggested on the campaign trail that as president he would be willing to go to Pyongyang before Washington, but he is making the US his first foreign destination since he was sworn in last month after a landslide election win.
Washington is the South's security guarantor and has more than 28,000 troops in the country to defend it from its neighbour, which has been intensifying missile tests -- including five since Moon's inauguration -- as it seeks to develop nuclear-capable ballistic missiles that could reach the continental United States.
US Pentagon chief Jim Mattis has labelled North Korea as "the most urgent and dangerous threat" while Trump has made halting Pyongyang's weapons programme a top foreign policy priority.
There have been misgivings about the first tete-a-tete between Moon and Trump, who is pushing for tougher sanctions against Pyongyang to curb its nuclear ambitions and whose administration has said military action was a possibility.
That would put Seoul on the front line of any retaliation from the North.
But analysts say their first encounter is likely to be low on drama with the two getting a sense of each other, rather than displaying jarring differences.
Trump's policy of "maximum pressure and engagement" has a wide range from diplomacy to sanctions, allowing for an "overlap" with that of Moon, who has never denied the need for sanctions even while seeking dialogue, said John Delury, a professor at Yonsei University.
"So there doesn't have to be a train wreck over North Korea policy," he told AFP.
Also high on the agenda is likely to be a controversial US missile defence system that has been installed in South Korea to guard against missile threats from the North.
Though parts of the Terminal High-Altitude Area Defense (THAAD) system are already in place, Moon suspended further deployment following a furious campaign of economic sanctions and diplomatic protests by Beijing against the US missile shield, dealing a blow to Washington's regional security policy.
Officially, the delay is to allow for a new, comprehensive environmental impact assessment, but analysts say the move is a strategic one by Moon to delay the tricky diplomatic situation he inherited.
- 'Ruffled feathers' -
Earlier this year Moon raised many eyebrows when he said in a new book that Seoul should learn to say "no" to Washington.
But analysts say the South Korean leader -- whose parents were refugees evacuated from the North by US forces -- will endeavour in Washington to portray their decades-old alliance as intact.
"Moon will seek to smooth ruffled feathers in Washington and give an impression that there is no daylight between the two allies," Sejong Institute analyst Hong Hyun-Ik told AFP.
Hong said that Moon "initially appeared to walk a tightrope between China and the United States" but was forced back to "the US orbit" under enormous pressure from his conservative political opponents.
The South Korean president advocates a two-phased approach to the North's nuclear issue, with Pyongyang first freezing its nuclear and long-range missile tests in return for the scaling back of annual US-South Korea military exercises.
In the second stage, the North's nuclear programmes would be completely dismantled in return for diplomatic ties and economic assistance.
The idea is similar to China's standing proposal of "dual suspension" of US-South Korea war games and the North's nuclear and missile tests, which Washington has already rejected.
For Moon, analysts say pursuing such an approach has been made more complicated by last week's death of American student Otto Warmbier, who had been jailed by the North.
Warmbier fell into a mysterious coma after being in prison for 18 months for stealing a political poster. He died days after being evacuated home, sparking outrage in the US.