One of the United States' most senior Navy commanders has acknowledged that accepting North Korea as a fully fledged nuclear power is "part of the dialogue" about how to deal with the rogue state.
I've long felt that in a bilateral framework, we could deter North Korea's nuclear weapons.
I really don't think North Korea is irrational. They have long had the ability to attack South Korea with some chance of success, but did not. In the post-Cold War era North Korea has lost both their Soviet backer and the ability to launch a conventional invasion, but the ability to hammer Seoul with high explosives and chemical weapons has remained. Yet North Korea has not attacked.
Maintaining their power is the ultimate goal of North Korea's ruling class. So a nuclear armed North Korea is admittedly far more dangerous on a wider front (including America eventually), but can be deterred.
As a bilateral issue.
The problem with accepting North Korea's nuclear power status is that Iran could purchase nuclear weapons from North Korea.
And even if Iran can be deterred from using nukes (I think there is enough doubt about that to make the prospect of a nuclear-armed Iran unacceptable), Iran will use nukes as a shield to be even more aggressive below the nuclear level. Is that something we want to encourage?
And you can't rule out that even if Iran's rulers won't use nukes that somebody in Iran who would love to use nukes could get access to one of them to do something horrific for the glory of Islam that the corrupt Iranian rulers are unwilling to do--most likely because they are a tool of the Great Satan or the Zionist Entity. (As they may tell themselves to justify mass murder.)
Have a super sparkly day.
UPDATE: This article is certainly reasonable in its discussion of coping with North Korea as a nuclear power rather than risking the uncertainties of war.
And if this was a problem restricted to North Korean nukes, I'd say the author has a strong argument. But the issue of broke North Korea selling nukes to a state like Iran is not raised.
I'm far more worried about North Korea selling nukes than I am of North Korea firing nukes at an American city.