SEOUL - Democratic presidential frontrunner Joe Biden says he would not meet with North Korean leader Kim Jong Un without preconditions. It is the latest evidence Biden would overturn parts of U.S. President Donald Trump’s outreach to Pyongyang.

"Not now, I wouldn’t meet without any preconditions," Biden said Tuesday during a Democratic debate in the midwestern state of Iowa. "Look, we gave him everything he’s looking for. The president showed up, met with him, gave him legitimacy, weakened the sanctions we have against him."

Biden has repeatedly criticized Trump’s willingness to meet with Kim, saying the strategy is ineffective and aimed more at creating headlines than addressing the North Korean nuclear issue.

At his campaign rallies, Biden has called Kim a "thug," "tyrant," and "dictator." In response, North Korean state media last year slammed Biden as an "imbecile," a "fool of low IQ," and a "rabid dog."

"I would not meet with, absent preconditions...a, quote, supreme leader who said Joe Biden is a rabid dog, (that) should be beaten to death with a stick," Biden said. "And he got a love letter from Trump right after that."

Instead, Biden said he would pressure China to convince North Korea to give up its nuclear weapons, and would attempt to reunify the relationship between South Korea and Japan, which has been strained over a trade dispute and historical tensions related to Japan’s use of wartime forced labor.

Unorthodox approach

Trump’s approach to North Korea during his first term as president has been a story of extremes. In 2017, Trump threatened North Korea with "fire and fury like the world has never seen." He also threatened to "totally destroy" the country.

In June 2018, Trump became the first sitting U.S. president to meet with a North Korean leader. At their first summit in Singapore, Trump and Kim signed a vague agreement to work toward the "complete denuclearization of the Korean Peninsula," but never agreed on what that meant.

The talks were stalled for most of 2019, after Trump and Kim failed to reach a deal at a second summit in Hanoi. Kim said earlier this month he is prepared for a "long-term" standoff with the U.S., saying his country should not expect sanctions relief.

North Korea has also threatened to end its self-imposed suspension of long-range missile or nuclear tests - a move that could totally upset the nuclear talks and would risk alienating Chinese and Russian support for the North.

North Korean officials have repeatedly stressed that while the Trump-Kim relationship remains positive, it does not mean the talks will succeed.

"Although Chairman Kim Jong Un has a good personal feelings about President Trump, they are, in the true sense of the word, 'personal,'" senior North Korean diplomat Kim Kye Gwan said on Saturday.

Will Trump’s approach endure?

It isn’t clear how much of Trump’s approach will outlast his presidency.

Many Democratic presidential candidates have criticized certain aspects of Trump’s North Korea strategy, saying it has been erratic and ratings-driven. But many of those candidates support the general idea of diplomacy with Pyongyang.

Vermont Senator Bernie Sanders, Massachusetts Senator Elizebeth Warren, and former Indiana Mayor Pete Buttigieg have expressed support for a step-by-step approach to North Korea’s denuclearization.

So far, that is further than Trump has been willing to go. Instead, Trump has insisted North Korea first agree to entirely abandon its nuclear weapons before the U.S. relaxes sanctions or gives other major concessions.

"If Trump's approach is erraticism, or insults combined with threatening fire and fury, or meeting Kim Jong Un for photo ops, then none of it will survive," says Van Jackson, a former Pentagon official who now lectures at Victoria University of Wellington in New Zealand.

Jackson says any current Democratic nominee will undertake a "serious run" at diplomatic engagement. "The thing that depends very much on the candidate (and their advisers) is how much we'll entertain sanctions relief and in what sequencing," he says.