WASHINGTON (Reuters) - When President Barack Obama counseled his successor Donald Trump on the global threats he should expect to face once he assumed office last year, a nuclear North Korea and its unpredictable leader were at the top of the list.

FILE PHOTO - U.S. President Barack Obama (R) greets President-elect Donald Trump at inauguration ceremonies swearing in Trump as president on the West front of the U.S. Capitol in Washington, U.S., January 20, 2017. REUTERS/Carlos Barria

But while the meticulous Obama practiced caution in handling Kim Jong Un, the blustery Trump succumbed to his own penchant for reality TV showmanship, culminating with his shock decision on Thursday to agree to meet with North Korea’s leader and become the first sitting U.S. president to do so.

Trump’s move is a sharp departure from 60 years of largely arms-length U.S. diplomacy when it comes to North Korea, not to mention his own previous bellicose rhetoric against Pyongyang. It also represents another instance in which the Republican Trump, a businessman who promised to shake up Washington, took a completely different direction than his Democratic predecessor.

Trump’s willingness to take that dramatic step is a reflection of his showboat style, throwing out the diplomatic playbook and putting himself in the spotlight, in addition to what aides say is his desire to resolve the North Korea crisis before it spins out of control.

“It’s hard to know whether this is just his supreme confidence that he can get a deal done with his own business experience, or whether he is calculating that he wins either way,” said Jim Steinberg, who served as deputy secretary of state under Democratic President Bill Clinton. “It’s always hard to know with Trump how well thought through this is.”

Obama, like his immediate predecessors, took a far more deliberate approach. As a presidential candidate he famously suggested meeting with U.S. enemies, and ended up relaunching Washington’s relationships with Cuba and Iran as president.

But he did not take that same step with North Korea, once warning Pyongyang that “you don’t get to bang your spoon on the table and somehow you get your way.”

Officials who served in Obama’s administration said there was a reason he never met with his North Korean counterpart.

“Our assessment was that the North Koreans weren’t serious about denuclearization and therefore sitting down to a summit just accords legitimacy ... to the regime, not just the leader, without achieving any concrete national security objective for the United States,” said Michael McFaul, U.S. ambassador to Russia under Obama.

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‘FEEL THE PRESSURE’

Trump’s advisers have harbored similar beliefs, but their boss appears ready to seize North Korea’s olive branch.

White House officials said that when South Korean national security adviser Chung Eui-yong relayed Kim’s invitation in an Oval Office meeting on Thursday, Trump readily agreed, feeling that U.S.-led sanctions were weakening North Korea.

“He believes that he has them at a disadvantage, and that they only made the gesture because they feel the pressure badly, and so this is a good time,” a senior White House official said.

While Trump’s move was welcomed by many experts as a way to get the two nations to step back from the brink of conflict, veterans of the Obama administration and other presidencies called for caution and careful diplomacy because of North Korea’s history of breaking agreements.

“We have to be clear-eyed that if this meeting is done in isolation, absent from a broader strategy that advances American interests, it will be a propaganda coup for Kim,” said Ned Price, a former national security council spokesman for Obama.

Clinton obtained an agreement to contain North Korea’s nuclear program and came close to a visit to Pyongyang after sending his secretary of state, Madeleine Albright, there in 2000. North Korea ended up abandoning the Clinton-era agreement.

Bill Richardson, Clinton’s U.S. ambassador to the United Nations who has made multiple diplomatic missions to North Korea, called the Trump-Kim summit a gamble.

“I worry that he might be falling into a trap,” Richardson said of Trump, adding he did not expect the first such summit to produce much but that Kim frequently has been underestimated.

Jay Lefkowitz, who was Republican President George W. Bush’s human rights envoy for North Korea, said Trump’s meeting is fraught with peril.

“I have some real anxiety about it. But on the other hand I’d rather have dialogue than missiles flying,” Lefkowitz said.