SEOUL/WILMINGTON, DELAWARE (REUTERS) - No more "Little Rocket Man", exchanging love letters or summit pageantry.

If Joe Biden is elected US president, American policy toward North Korea is likely to see less emphasis on personal dealings with leader Kim Jong Un, and more focus on allies and working-level diplomacy, campaign advisers and former officials say.

President Donald Trump has said he will make deals with North Korea "very quickly" if re-elected on Nov 3.

Pyongyang officials, however, have said while Kim still has a good relationship with Trump, they have to look ahead to a time when Trump isn't president.

Last year, North Korea lashed out at Biden, calling him a"rabid dog" that should "be beaten to death" for comments seen as disparaging of Kim.

Biden, who has a solid lead in most opinion polls, cited those threats in January when he said he would not meet with Kim unless unspecified preconditions are met.

After months of trading threats and insults - Kim was"Little Rocket Man" and Trump a "deranged US dotard" - Trump became the first sitting US president to meet with a North Korean leader when he held a summit with Kim in Singapore in 2018.

The two leaders met twice more, and exchanged what Trump called "beautiful letters", but failed to resolve a standoff over North Korea's nuclear weapons.

"There's no question that the era of love letters will be over," one Biden policy adviser, speaking on condition of anonymity, told Reuters.

Biden told The New York Times he would not continue the personal diplomacy with Kim, calling the meetings a "vanity project" that should only happen if coupled with "an actual strategy that moves the ball forward on denuclearisation."

'ALLIES AND PARTNERS'

Biden would not shut the door to diplomacy, but instead"empower negotiators and implement a sustained and a coordinated effort with allies and partners" to pressure and incentivise North Korea to denuclearise, while also drawing attention the country's human rights abuses in a way that has been lacking in current US policy, the Biden adviser said.

Biden was vice president under Barack Obama, and some parts of his policy would likely be similar to Obama's "strategic patience", which sought to isolate North Korea and not offer diplomatic rewards for its provocations.

"Many advisers in Biden's campaign were part of the'strategic patience' team, which is pro-alliance and takes orthodox approaches to foreign policy, including North Korea politics," said Chang Ho-jin, a former South Korean presidential foreign policy secretary who worked with several Biden aides.

"North Korea wouldn't have to face fears of unpredictable military action as Trump had floated, but would likely suffer from tighter screws."

Biden's promise to work more closely with allies may be complicated by South Korean President Moon Jae-in's push for more engagement with North Korea and looser sanctions, while downplaying human rights issues.

"That could create a discord with Seoul," said James Kim, a research fellow at the Asan Institute for Policy Studies.

A PROVOCATION BY PYONGYANG?

Kim has also made significant progress in advancing his military capabilities since Biden last held office, successfully testing North Korea's largest nuclear bomb and missiles capable of striking anywhere in the United States.

The US arms control community is likely to have a strong voice in a Biden administration and will argue it is time to accept the idea that North Korea is now a nuclear power, said Evans Revere, a former US negotiator with North Korea.

But that approach would effectively grant North Korea's long-time goal of cementing its nuclear status, and a Biden presidency will almost certainly take a more hard-nosed approach, likely prompting pushback from Pyongyang, Revere said.

"If Biden wins in November, we can expect North Korea to take a dramatic step later this year, possibly by conducting a nuclear or ICBM test, to warn the new administration away from this path," he said.

The Biden adviser declined to elaborate on what Biden might do if North Korea returns to nuclear or ICBM tests.

Jung Pak, a former CIA analyst who now works at the Brookings Institution and provides informal counsel to the Biden campaign, said any North Korean provocation could be used by a new administration.

"A nuclear or ICBM test by North Korea would provide an opportunity for the new administration to highlight the threat that the Kim regime poses and try to build some consensus or agreement with our allies on a coherent North Korea policy," she said, while noting that she does not speak for Biden's campaign.

"That is, don't let a good crisis go to waste."