WASHINGTON -- The U.S. has responded to North Korea's latest nuclear test by doubling down on pressure, threatening to cut off trade with anyone doing business with the rogue state and issuing more dire warnings about possible military action.
The administration of President Donald Trump is believed to consider the testing of nuclear weapons or intercontinental ballistic missiles a red line that, if crossed, would merit a military response.
The government has not officially acknowledged the existence of such a threshold, seeking to retain a degree of flexibility. The hope was that comments by security experts and other unofficial sources about a red line would serve to curb Pyongyang indirectly. But the latest nuclear test, coming on the heels of the two ICBM launches in July, made clear that this strategy has failed.
Leaning on Beijing
After the test, Trump took to Twitter to turn up the pressure, declaring that "the United States is considering, in addition to other options, stopping all trade with any country doing business with North Korea."
This threat seems aimed squarely at China, which accounts for around 90% of North Korean trade. By bringing up even the possibility of cutting off China-U.S. trade -- a move seen as infeasible given the damage it would deal to the American economy -- Trump aims to push Beijing to do more to rein in Pyongyang.
Treasury Secretary Steven Mnuchin on Sunday told broadcaster Fox News that he is drawing up a sanctions bill for Trump's consideration. "We are going to work with our allies, we'll work with China, but people need to cut off North Korea economically," he said.
Mnuchin did not deny the possibility of sanctions against individual businesses. "Anybody that wants to do trade or business with [North Korea] would be prevented from doing trade or business with us," he asserted.
The U.S. also hopes to persuade China to cut off its oil supply to North Korea. Despite growing frustration with Pyongyang's nuclear and missile programs, Beijing has been reluctant to take such a step, given the havoc an embargo could wreak on its neighbor.
The idea has also been floated of sanctions blocking major North Korean exports not covered by existing measures, such as clothing.
The American response is widely expected to involve further flexing of military muscle as well. B-1 bombers from Guam and cutting-edge F-35 stealth fighters flew over the Korean Peninsula together for the first time Thursday. Washington is also considering sending a carrier strike group to the area again.
Trump met Sunday afternoon with Vice President Mike Pence, Defense Secretary James Mattis and other officials involved with national security policy to go over military options. Asked that day by reporters whether he could order an attack on North Korea, the president said "we'll see."
A preemptive strike is not a realistic option, a former senior U.S. official said, echoing a widespread view. Pyongyang would undoubtedly retaliate by attacking South Korea and Japan.
Yet Mattis affirmed Thursday, in unusually strong terms, that military options remain on the table. "Any threat to the United States or its territories, including Guam, or our allies will be met with a massive military response, a response both effective and overwhelming," the defense secretary told reporters after the meeting.
"We are not looking to the total annihilation of a country, namely North Korea, but as I said, we have many options to do so," he said.
Speculation has also swirled about the U.S. launching an operation to kill leader Kim Jong Un. Some attribute Kim's periodic long spells of silence to fears of such assassination attempts.
Japan left in the lurch?
Alarm at the growing possibility of North Korea acquiring a nuclear-tipped ICBM capable of reaching the mainland U.S. may drive Washington to seek a compromise to avoid this worst-case scenario. It could, for example, agree to recognize Pyongyang as a nuclear power in exchange for a moratorium on ICBM development.
Such a deal would be a nightmare for Japan. The country would still face the threat of North Korea's intermediate-range missiles, and it could be forced to give up on learning the fates of Japanese citizens abducted by Pyongyang in the 1970s and 1980s.
Such a situation could also provide fodder for those who argue that Japan and South Korea should acquire their own nuclear weapons, raising the risk that nonproliferation efforts in the region could collapse.