Arriving in Asia, Gen. Joe Dunford says he is prepared for war, but supporting Secretary of State Rex Tillerson’s efforts

OSAN AIR BASE, South Korea, The Wall Street Jouranl, Auguust 13, 2017—The Pentagon’s top military officer said here Sunday the focus remains on finding a diplomatic solution to the North Korea missile crisis, even as the military works up viable options in case they become necessary.

Amid heated rhetoric between President Donald Trump and North Korea’s rogue leader, Kim Jong Un, the military is quietly supporting Secretary of State Rex Tillerson’s effort to use diplomatic and economic pressure to avert war.

“As a military leader, I have to make sure that the president does have viable military options in the event that the diplomatic and economic pressurization campaign fails,” said Chairman of the Joint Chiefs of Staff Gen. Joe Dunford in his first public remarks since the crisis escalated with North Korea’s launch of a second intercontinental ballistic missile late last month.

“Even as we develop those options, we are mindful of the consequences of executing those options, and that makes us have more of a sense of urgency to make sure that we’re doing everything we absolutely can to support Secretary Tillerson’s current path,” he said.

Gen. Dunford began a scheduled swing through the region Sunday, with a stop here to meet with South Korean President Moon Jae-in, along with newly appointed defense officials and commanders. Gen. Dunford leaves Monday for Beijing and will also visit Tokyo this week, defense officials said.

He declined to provide an assessment of the current situation until he had met with officials on the ground. But while the U.S. military in the region is prepared for war, it isn’t necessarily preparing for war, other military officials said.

No additional forces have been sent to the Korean Peninsula as a result of the crisis, and there has been no new deployment of ships or submarines. The more than 28,000 U.S. troops stationed in South Korea haven’t been put on special alert, military officials said. And, the fact that Gen. Dunford and his wife, Ellyn, are traveling in the region this week reinforces the sense that there is no imminent threat of war.

Many military hands who know the Korean Peninsula are quick to point out that tensions and threats from North Korea—Mr. Kim this month pledged to lob missiles toward the Pacific island of Guam—are nothing new. “We should keep in mind that this is not the first time we’ve had this level of rhetoric, it’s not even the first time they’ve threatened Guam,” an official said.

Still, as Mr. Trump continues to tweet about U.S. posture, saying the military is “locked and loaded” and ready to fight, the military hasn’t shied away from sending its own signals. In recent days, the U.S. touted a flyover by a pair of its B-1B strategic bombers, an event it rarely announces publicly.

And, in the wake of each of North Korea’s two intercontinental ballistic missile launches last month, the U.S.’s Eighth Army blasted missiles using the Army Tactical Missile System, or ATACMS, to counter the threat. South Korea simultaneously launched its own Hyunmoo Missile II system.

An escalation of threats between Washington and Pyongyang has rattled world leaders, injected uncertainty into markets, and sparked fear of a nuclear showdown. The WSJ’s Shelby Holliday takes a look back at the week 

The U.S. military is keeping its cards close to its chest, declining to talk publicly about what it might do militarily. A pre-emptive strike on North Korea remains unlikely, military officials have said.

Still, persuading Mr. Trump of a certain course of action typically requires advisers to make the argument repeatedly, officials have said. Military advisers who don’t believe in a pre-emptive strike know they will have to keep the president persuaded that the U.S. would be unwise to take that approach.

Gen. Dunford said the purpose of his Monday visit to Seoul, which sits just 35 miles south of the border with North Korea, is to reassure a critical ally. He is expected to examine the options the U.S. and South Korean militaries could execute if a conflict were to come to pass, officials said.

He is also set to discuss with Mr. Moon the deployment of the Terminal High Altitude Area Defense, or Thaad missile defense system. After extensive discussion between the U.S. and South Korea, a Thaad battery was deployed near a golf course in South Korea this spring to help defend against any missile launches from the north. Only two of the six launchers were deployed and the U.S. and South Korea are now in talks to deploy the system with its full complement of launchers, U.S. Pacific Command officials said.

Meantime, the U.S. and South Korea will soon begin their annual joint military exercises, known as Ulchi Freedom Guardian, a two-week command and control exercise that primarily tests the integration of U.S. and South Korean forces.

U.S. defense officials said the exercise isn’t expected to amount to a large show of force and that there are no plans for expansion under the current circumstances. Ulchi Freedom Guardian, or UFG as it is called, typically sees an additional 200 to 300 U.S. troops here for the next couple of weeks.

Meanwhile, as people on Guam prepare for the potential of an attack, U.S. military officials acknowledge quietly that Pyongyang’s capabilities make it unlikely Mr. Kim could fulfill his pledge to lob missiles toward the island and get them anywhere close.

The North Korean leader hasn’t proven he can make the technology work with any precision, an official said. But North Korea has moved faster to develop its capabilities than the U.S. believed it would. Pacific Command officials said they have to take Mr. Kim at his word.

“They have proven through these recent launches that they have increasing range there,” the U.S. Pacific Command official said. “We have to take these threats seriously.”