Part 2 in a Series

Donald Trump was elected on a platform of politics not as usual. So it is fitting he inherits a world in flux. Post-World War II rules are dying, old alliances are shifting and traditional roles are being shed. While Trump is a giant question mark on the world stage, NBC News’ Chief Global Correspondent Bill Neely looks at major international challenges the president-elect faces upon inauguration on Jan. 20.

North Korea and its leader Kim Jong Un pose an uncompromising challenge to the new administration.

Kim Jong Un Wong Maye-E / AP

Within four years, some experts warn Kim may have a nuclear warhead capable of reaching the West Coast of the U.S., as well as submarines able to conduct swift surprise attack on America’s allies. So it will be crucial that Donald Trump restrain and engage Kim.

In October, a senior North Korean official told NBC News the country is targeting mainland America with a nuclear weapons program it will not halt.

“Offense is the best form of defense,” Lee Yung Pil said.

He promised more nuclear tests, accused the U.S. of wanting to remove North Korea’s leadership and argued that American policies, including sanctions, have backfired.

North Korea's Arms Race

Turning North Korea into a nuclear power has defined Kim’s five years in power. Under him, the country has conducted three of its five nuclear tests.

Kim is also pursuing missile technology it would need to attack South Korea, as well as Japan and the 50,000 U.S. troops it hosts. Kim's regime also has designs on the key U.S. military outpost of Guam and the U.S. mainland itself. North Korea has even joined the space race and put satellites into orbit, possibly for the same reason.

So it is no surprise that, according to the Wall Street Journal, the Obama administration warned Trump’s transition team that the nuclear-armed country should be considered the incoming White House team’s top national security threat.

As a candidate, Trump called Kim a "maniac,” although it is unclear if that description was necessarily all negative. "You've got to give him credit," he added.

Trump also said he'd be willing to meet Kim over a hamburger — a suggestion that Pyongyang dismissed out of hand, presumably not because of Trump's choice of food.

Related: Here's How Trump Vowed to Deal With 'Bad Dudes' Like Kim

The Shortcomings Of Sanctions

The United Nations’ toughest economic sanctions ever did not stop North Korea from conducting its the most powerful nuclear test to date on Sept. 9 — what Pyongyang claims was a powerful hydrogen bomb.

North Korea has dodged the worst effects thanks to its ally, sponsor and neighbor China. For its part, China argues it cannot deal with the North Korean nuclear issue alone and that a solution lies with the two main protagonists — Pyongyang and Washington — engaging directly.

As one U.S. official said recently, sanctions are designed to bring North Korea to its senses not to its knees. Whatever their intention, they don’t appear to be working. In Pyongyang, it is possible to have a morning cappuccino made with Starbucks coffee beans and an evening drink of Argentine wine followed by the finest Scotch whisky.

Trump could pursue even more targeted sanctions, but past measures have clearly not stopped the North Korean nuclear program so what would be the point in that?

In fact, Obama's Director of National Intelligence James Clapper said recently that the goal of getting the North to give up its nuclear program is “probably a lost cause.”

“They are not going to do that — that is their ticket to survival. They are under siege and they are very paranoid,” he said. “The best that we could probably hope for is some sort of a cap.”

The Confrontation Strategy

The new president could ditch the United States’ decades-long policy of “strategic patience” and instead confront Pyongyang.

Related: How China Could Pose the Biggest Challenge for Trump

To some degree, the U.S. is already doing that by holding increasingly large military exercises with ally South Korea that include rehearsals for regime change in Pyongyang. It flew B-1 nuclear bombers off North Korea in September as a show of force.

Trump could ramp up this approach, but a direct, preemptive strike on North Korea is most probably not on the table — the risk is just too big. Pyongyang would immediately retaliate by blitzing South Korea’s capital Seoul, which is only 50 miles from its border.

The exact capabilities of Kim’s long-range missiles are not clear. But it is safe to say he would try to retaliate to a foreign attack. And no one doubts he has a nuclear capability, however weak.

The Accommodation Option

There is another, as yet untried approach that the new administration might consider.

Rather than trying to prevent or reverse North Korea’s nuclear program, the U.S. might quietly accept it and manage the consequences.

As it is, the North sees its nuclear program not as a bargaining chip but a vital part of its national security. It sees the world through the lens crafted by President George W. Bush, who in 2002 declared the country part of America’s “axis of evil” that encompassed Iraq and Iran.

Pyongyang undoubtedly watched carefully as Iraq’s Saddam Hussein was overthrown and hanged after a U.S. invasion. And the regime surely noted the invasion was justified by allegations Iraq was hiding weapons of mass destruction, charges that turned out to be false. Later, Col. Moammar Gadhafi of Libya — another American bugbear who had harbored and then abandoned ambitions of developing a nuclear arsenal — was toppled and murdered during a U.S.-backed uprising.

Kim’s nuclear weapons are his defense against going the same way as Saddam and Gadhafi.

Clapper notes that accepting North Korea’s inconvenient arsenal and trying to cap it may require “some sort of inducements.”

So Trump has difficult choices ahead, given that the decades-old policies of sanctions, threats, isolation, talks and concessions have had little impact.

The China Dilemma

Failing again under Trump would send a signal of American weakness in a region where the balance of power is in question, with China challenging America’s right to play a preeminent role in Asian affairs.

And here’s where the North Korea question joins an even bigger one for the new president: an increasingly assertive China.

Related: Trump Inherits an Increasingly Divided World

Trump has often suggested China crack down on its smaller neighbor. But while Beijing has no love for the instability North Korea creates, it is also in its interests to have a buffer zone against U.S. forces in the south of the peninsula.

The last thing Beijing wants is a collapsed North Korea, which could result in American troops right on its border in a reunited Korea. So for China, the status quo may be the least-bad option.

But if the new president concludes that a nuclear-armed North is inevitable, it may be forced to propose new arms control and nuclear talks that include Israel, Pakistan, India, Japan, Saudi Arabia and other states that may want the weapons. That is unlikely, although as a candidate Trump criticized the current international nuclear status quo that prevented allies like Japan from developing nuclear arsenals for their own protection.

“At some point we have to say, you know what we’re better off if Japan protects itself against this maniac in North Korea,” candidate Trump said when asked whether he would abandon longstanding U.S. policy of a non-nuclear Japan.

So how the Trump team will handle North Korea, the region and nuclear proliferation is not yet known — the president-elect has not addressed the issue specifically since Nov. 8.

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