How Trump can stop North Korea's nuclear threats against the U.S.

In their first verbal standoff, North Korean leader Kim Jong Un indicated his country is in the final stages of testing a missile with a nuclear weapon that can reach the United States, and President-elect Donald Trump has vowed that "won't happen."

Trump's options for making good on that tweet sent Monday range from diplomacy to a pre-emptive military strike.

Here are some options for dealing with the North Korean nuclear threat, according to former U.S. negotiators, arms control experts and analysts who’ve studied the region.

WORK THROUGH CHINA

Trump could start by trying to work with China rather than antagonize it, said Chris Hill, who led U.S. negotiations on North Korea’s nuclear program for President George W. Bush.

“If there is a solution, that solution will be with China,” North Korea's most important ally, said Hill, now dean of the Josef Korbel School of International Studies at the University of Denver. “The president-elect should be careful about picking fights with China over trade or the one China policy because he will need a lot of his capital for North Korea.”

Since his election, Trump accepted a congratulatory phone call from Taiwanese President Tsai Ing-wen. That was a breach of U.S. policy, which does not recognize Taiwan's sovereignty. (China considers Taiwan a breakaway province that someday will be reunited with the mainland.) Trump later questioned whether the United States “should be bound” by the “one China” policy, unless China cooperates on “other things, including trade.” The "one China policy" recognizes the communist leaders in Beijing as the only legitimate Chinese government.

“I would put cooperation with China on North Korea above any efforts to change the status quo of the Taiwan relationship or the (China-U.S.) trade relationship,” Hill said.

N. Korea says intercontinental missile is near. Trump says 'It won't happen!'

TOUGHEN REGIONAL DEFENSES

Trump could increase deterrence activities along with allies South Korea and Japan, said Richard Bush a senior fellow at the Brookings Institution, a Washington think tank.

This means moving ahead and expanding plans to deploy the Terminal High Altitude Area Defense missile shield that President Obama promised South Korea, where nearly 30,000 U.S. troops are stationed. It also means expanding live-fire joint exercises with South Korea and Japan, which would require North Korea to devote resources to monitor and respond to military activities on its borders that it can't tell are only drills or invasion preparations.

The U.S. also could fly more B-52 strategic bombers over North Korea and engage in more operations “to influence what’s going on in the public mind of North Koreans,” Bush said. Expanding existing efforts to smuggle cellphones and CDs with South Korean soap operas into North Korea would break the isolation the regime tries to maintain over its people, Bush said.

“It’s breaking down, and the more it breaks down the better,” because that weakens the regime, he said.

OFFER ECONOMIC INCENTIVES

Trump should offer North Korea economic aid if it agrees to stop testing nuclear weapons, said James Acton, co-director of the Nuclear Policy Program at the Carnegie Endowment for International Peace.

The North participated in such negotiations with Presidents Clinton, Bush and Obama, and even agreed to deals that it then cheated on and abandoned. Acton conceded that approach now is “unlikely to succeed,” given North Korea's pattern, but he said it is worth trying again. “It’s the least bad of a really bad bunch of options,” he said.

IMPOSE NEW SANCTIONS

Increased sanctions on North Korea is another option, but it, too, has been tried and failed to achieve the desired result.

“Economic sanctions, increasing air deterrence efforts on the Korean peninsula and … encouraging China to use economic means to pressure North Korea — that package of actions and programs (is) connected to the realities we face,” the Brookings Institution's Bush said. “It also sounds a lot like the Obama administration’s policies.”

Despite sanctions, North Korea continues to conduct nuclear tests — including two in 2016 — and missile tests in violation of United Nations resolutions opposing them.

PRE-EMPTIVE NUCLEAR STRIKE

If Trump wants to “quickly decapitate the head of the snake” and do it without mobilizing 100,000 U.S. troops to invade North Korea, he could order a military strike on the capital, Pyongyang, said Robert Kelley, a former director at the U.N.’s International Atomic Energy Agency.

Kelley, now a fellow at the Stockholm International Peace Research Institute, said he is not advocating a nuclear strike, but Trump — who has made clear he’s "ready to throw the old way of doing things out the window” — might consider the option.

“In the short term it would remove the threat,” Kelley said.

Acton said a pre-emptive nuclear strike or even a conventional strike would be unlikely and a huge risk.

“Presumably the nuclear weapons are located elsewhere, and commanders may have launch authority to use them in the event the leadership is destroyed,” Acton said. “Going after Kim Jong Un and a large part of his leadership structure doesn’t necessarily remove the threat.”