It seems President Moon has made himself a pretty specific red line with North Korea that in my opinion he has no intention of actually enforcing:
The President’s definition of a “red line” for North Korea has fueled controversy, with critics questioning its adequacy.
At a press conference to mark his 100th day in office Thursday, President Moon Jae-in said that he would consider North Korea had crossed a red line “if it completes development of an intercontinental ballistic missile (ICBM) and weaponizes it by fitting a nuclear warhead on it.”
He also said, “North Korea is nearing the threshold of the red line.”
Some people, including Moon’s aides, interpreted the rare remarks as a warning to the North on its rapid progress in developing nuclear weapons and missiles. But criticism of his “diplomatic immaturity” was prevalent.
Pundits expressed concerns that the statement narrowed the Moon administration’s policy options in dealing with North Korea.
“Moon must be the first leader in the world who went into details of what constitutes a red line,” said Nam Sung-wook, a professor at Korea University’s department of unification and diplomacy. “Keeping ambiguity suits national interests. Moon may have said so to prevent a U.S. preemptive attack, but still, it exposed our intentions.” [Korea Times]
You can read more at the link.