Kim Jong Un is a tyrant. Talk of peace in Korea doesn't change that

NN) Even without the shadow of nuclear threats hanging over the Korean Peninsula, the sight of North Korea's Kim Jong Un and South Korea's Moon Jae-In embracing one another and spending a full day in substantive conversation would have been enough to stir emotion.

The two Koreas -- first divided in 1945 with the end of World War II in Asia and then the site of a horrific civil war and international conflict -- have seen enough violence and tragedy in the last 70 years to fill a few centuries.

So when the leaders of the two Koreas made an announcement from Panmunjom aiming to "open up a new era of peace" and ultimately end the Korean War, it is natural that optimism will reign supreme, along with feelings of relief.voiding all of the messy details of the statements and policy promises made in Panmunjom, and leaving Kim Jong Un expressly out of it, Donald Trump's tweet seemed to sum things up.

There is no doubt that such a meeting gives ground for optimism. But we must not ignore the myriad problems that peace in Korea still needs to navigate -- not least that North Korea is still a brutal dictatorship.

Since the two Koreas began negotiations in 1972, there have been a number of agreements made that would do things similar to the new agreement. In 1991, the two Koreas jointly pledged to set up a "peace regime" that would end the Korean War, but ended only two short years later on the brink of conflict over the North's nuclear program.

Nearly every detail mentioned in the ambitious and exciting new Panmunjom Declaration has been worked through toward failure in the past, whether family reunions -- where North Korea effectively holds the cards and controls the pace of contact -- to Pyongyang's vague promises to denuclearize, to promises to link up the two nations' rail infrastructure.

The Demilitarized Zone and the less-known but as important Northern Limit Line in the Yellow Sea have remained real trigger points for inter-Korean clashes.

It may be that things outside of Kim's control -- like a random defection across the line -- or a mudslide that moves landmines into areas patrolled by Southern troops (as allegedly happened in August 2015) will escalate again the war of words between the two sides.

The tables that Kim and Moon met at were appropriately small -- as befit the desire to make this summit more of an intimate gathering for the leaders, rather than a ceremony full of pomp and circumstance that would be expected in Seoul or Pyongyang. But the table will need to get significantly larger to incorporate the United States and China if the Armistice agreement of 1953 is to be updated, altered, or done away with.

Japan is a potential lifeline economically for North Korea and a key US ally, but is likely to feel both left out and ganged up upon as the Koreas align more closely with one another. If the Trump administration begins to flirt with troop withdrawals, there will be more pressure to expand American military operations and bases in Okinawa -- always a sensitive issue.

The Soviet Union was not party to the Armistice, and Russia has been left out of the Panmunjom Declaration. But it is a key player with respect to balancing North Korea's foreign relations, and has significant leverage thanks to its coal and transportation ties. Will Donald Trump insist that his good friend Vladimir Putin have a seat at the table when it comes to negotiating North Korea's nuclear status?

And US-China relations with respect to Korea are not only difficult to align but can interfere with inter-Korean politics as the great powers get drawn in -- a recurring theme in Korean history of the last 150 years.