"China did suspend its coal imports from North Korea for a year -- but only after it had already purchased its allowed quota under UN sanctions. Beijing may have anticipated that talks were in the offing and positioned itself to claim credit for coaxing Pyongyang to the negotiating table," he said.

He said that the North Koreans have indicted they're open to talks, but not to commit to complete denuclearization first.

Pyongyang may be willing to suspend its nuclear and missile programs only if Washington addresses its security concerns in return, he said.

"Will tougher sanctions compel it to the table on US terms, even force it to collapse? Proponents say they will take time to work. How long? Two years? Five years? Ten years? In the meantime, how many nuclear and missile tests will the North carry out? How much fissile material will it make? How many ICBMs will it field?" Sigal said.

"It could take three years or more for the North to develop its ICBM. Cyberwarfare could at best delay the inevitable -- if that.

Contemplating preventive war could rupture US alliances in Asia.

The only way out of Trump's predicament is acceptance -- resume talks with North Korea, the sooner the better, to probe whether it is willing to suspend arming," he said.

The op-ed piece reflects growing calls in the US for reopening negotiations with Pyongyang for a possible freeze on its nuclear and missile programs, as the regime has significantly accelerated its nuclear development with two nuclear tests and a number of missile launches since last year.

Last month, the North test-fired a newly developed intermediate-range ballistic missile powered by solid fuel in its first provocative act since Trump took office. On Monday, the North fired a barrage of four missiles that flew about 1,000 km before crashing into the East Sea. (Yonhap)