Seoul, Japan at risk in US war scenarios against North

Three weeks before becoming president, Donald Trump weighed in on the threat of North Korea developing a nuclear warhead capable of reaching the U.S.: “It won’t happen,” he vowed on Twitter.

Now planners are contemplating what a U.S. strike to prevent that development might look like, and the options are grim.

Analysts estimate that North Korea might possess 10 to 25 nuclear weapons, with launch vehicles, air force jets, troops and artillery scattered across the country, hidden in caves and massed along the border with South Korea. That’s on top of what the U.S. estimates to be one of the world’s largest chemical-weapons stockpiles, a biologicalweapons research program and an active cyberwarfare capability.

And with Seoul and its 10 million residents just 35 miles south of the border — well within North Korea’s artillery range — any eruption of hostilities could have devastating human and economic costs. That’s why the North Korean dynasty founded by Kim Il Sung has long hinged its survival, in part, on a warning that any attack could provoke all-out war.

“Unless you were in a crisis situation where we thought the North Koreans were getting ready to attack us, a pre-emptive strike against the North Korean nuclear and missile program is simply not a practical option,” said Gary Samore, a former White House coordinator for weapons of mass destruction, proliferation and terrorism who is at Harvard University’s Belfer Center for Science and International Affairs. “This has always been the problem for the U.S. and our allies.”

After Trump ramped up his rhetoric against North Korea this month, the Pentagon ordered the USS Carl Vinson to head toward Korean waters, where the aircraft carrier is expected to arrive next week. Trump has warned that if China — North Korea’s closest ally — can’t help rein in the regime, the U.S. and its allies will.

Among the war-game scenarios at the Pentagon’s disposal are an airstrike using precision-guided munitions — launched from submarines or stealth aircraft — against the Yongbyon nuclear-reactor facility, where North Korea has produced plutonium for its bombs.

That was an option weighed as far back as the Clinton administration, according to two former Pentagon chiefs. “We were highly confident that it could be destroyed without causing a meltdown that would release radioactivity into the air,” Ash Carter and William Perry wrote in a report for the Belfer Center in 2002. That plan was seen as a worst-case scenario.

Another option would be an attack on facilities at Punggyeri, the mountainous site in the northeastern part of the country where previous underground nuclear tests have been conducted. Evading radar, B-2 bombers built by Northrop Grumman could drop “bunker buster” bombs to try to do the most underground damage.

Or, if the U.S. learned that North Korea was preparing to test an intercontinental ballistic missile — and it had confidence in where that missile would be launched — it could take out the vehicle, or try to shoot it down.

That probably wouldn’t save Seoul from devastation if North Korea responded to such a strike with a barrage of artillery or shorter-range missiles. In its defense, South Korea would go after the artillery that North Korea has massed near the demilitarized zone and use its defensive Patriot missiles and anti-missile ships.

In its final months, the Obama administration agreed to deploy a missile defense system known as Thaad to South Korea, but that shield is not yet fully installed.

The decision to attack isn’t Trump’s alone. Because South Korea would bear the brunt of any North Korean response, the highest levels of the South Korean military and government would “all have a say in making momentous decisions,” such as “do we, or do we not, go to war,” said Bill McKinney, a retired Army colonel who was involved in U.S.-Korea military relations and planning for more than 40 years.

Any unilateral military action by the U.S. would threaten deep damage to its alliance with Japan, which also would be put at risk. Such action also could bring China and the U.S. into conflict.

The situation facing the U.S. grows more dire as North Korea moves toward its goal of developing an intercontinental ballistic missile with a nuclear warhead that could hit the U.S. mainland. But in weighing possible responses, the administration must also decide how urgent that threat really is.

North Korea will need until at least 2020 to develop a nuclear weapon with that reach, according to John Schilling, a satellite specialist with the Aerospace Corp. The country still hasn’t tested an ICBM.

“This isn’t an imminent crisis,” Schilling told reporters Tuesday in a briefing organized by 38 North, a website that focuses on North Korea. “The imminent threat is to South Korea and Japan.”

But Schilling referred to the regime’s unpredictability, saying: “Probably their first response will not be nuclear — it might not even involve missiles. They have several levels of escalation to go before they get to nuclear weapons.”

[WONG MAYE-E/THE ASSOCIATED PRESS] North Korean soldiers march across Kim Il Sung Square during a military parade April 15 in Pyongyang.