This much is basically public knowledge. But behind the scenes, even the supreme leader, Kim Jong-un, feels threatened. And there is apparently a feeling among the top leadership in North Korea that if Kim attends the Singapore summit with Donald Trump, the military will take advantage of his absence to stage a coup.

North Korea is far more than a run-of-the-mill dictatorship. It is a paranoid gangster state, enormously corrupt, with various factions always at odds as they jostle for power.

Business Insider:

Citing sources familiar with the preparations, The Washington Post reported Tuesday that Kim was less concerned about meeting Trump than he was about what might happen at home in Pyongyang while he's gone. Kim is apparently concerned that the trip to Singapore may leave his government vulnerable to a military coup or that other hostile actors might try to depose him, sources told The Post. The Kim dynasty has ruled North Korea since the country's inception following the armistice in 1953. Rumors of a simmering military revolt in North Korea are precisely the kind of thing that emboldened Kim to keep a tight grip on power over the years, according to some experts. "The notion that Kim is secure in his power is fundamentally wrong," Victor Cha, a director for Asian affairs for the National Security Council during the George W. Bush administration, wrote in a 2014 opinion column. "Dictators may exercise extreme and draconian power like Kim, but they are also pathologically insecure about their grip on the throne," Cha said. "All of the public speculation about coups or interim leaders would feed the paranoid impulse of a dictator to correct that perception as quickly as possible, even if it were misplaced."

As if to confirm those worries, Strategy Page is reporting that Kim shook up his military high command in just the last few days.

May 18, 2018: In North Korea Kim Jong Un again reorganized the senior military leadership. This time there were not a lot of dismissals but instead, a lot of senior commanders were moved to other senior military posts. Kim has been wary of the generals ever since he took power in 2012. Ge was the youngest national leader ever in North Korea and many of the old timers doubted young Kim could handle it. Kim soon executed a number of senior generals and retired many more. ... Another sad fact is that few North Korean military personnel even remember the glory days (the 1980s) of the Cold War when Russia (as the Soviet Union) was supplying new weapons and support for older ones and the troops had fuel for training. All that disappeared in 1991 and the North Korean military is still suffering massive deprivation.

The wild card is China. Things are so bad in North Korea that a steady stream of refugees is crossing the border into China. The Chinese government hardly knows what to do with these people. There is a real fear on the part of Kim that if the refugee problem gets much worse, China will support a coup against him. China is also tired of the brinkmanship between Kim and Trump and could support a coup to bring more stability to the peninsula.

No wonder Kim fears his own military. At least this time, he apparently didn't tie any of them to the barrel of an anti-aircraft gun and pull the trigger.

Washington is well aware of the situation, and the Trump administration's public doubts about the summit taking place may have something to do with the whispers his people getting from North Korea about a fearful Kim. But North Korea's situation is beyond desperate, and Kim may be forced to take a risk he wouldn't ordinarily take to save his regime from economic and social collapse.