Regarding North Korea
As the debacles of Vietnam and the 2nd Gulf War make clear to the thinking American, patriotic service can be rendered to the nation by influencing the nation away from armed conflict with a foreign power. Indeed, this was America's founding vision of democracy!
To speak specifically, as I have before against the prevailing wind of war, the current state of affairs regarding North Korea is not desirable... The political will to de-nuclearize the Korean penninsula simply and ultimately does not exist.... within the U.S.A. and regarding the wider world.
The Chinese do not see North Korea as a loose cannon, but as an ally, a beloved younger brother whose defeat would be as if their own. As for the North Koreans, their current leadership is convinced(perhaps quite rationally) that if they gave up their nuclear missiles, the U.S. would oust them from power and hunt them down like dogs, as we did in Libya under similar circumstances. Their nation is rallied around them, and they are bound and determined to be a nuclear state.... even unto mutual destruction.
The only way that actual de-nuclearization MIGHT, just might be accomplished is if all the signs made it clear that the American people were genuinely willing to have a two-sided nuclear war in order to accomplish that end. The signs won't point to that because that's not the truth... most of the American intelligentsia realize that the regime in North Korea is on the whole a rational player. They would just prefer them to be non-nuclear. That's not enough: That just won't work.
Furthermore, it should be bourne in mind that the North and South Korean peoples have a deep bond of patriotic affection for each other. Separated by ideology, they are united by their unique identity as Koreans. Both sides dream of eventual re-unification, but are kept apart by a difference in archaic ideologies.
Rational thinkers realize that the time to disempower North Korea's nuclear arsenal passed long ago... They now have not only conventional nuclear weapons but Hydrogen bombs and the missile technology to strike Japan and Guam, but the whole of western Europe.
At the end of the day, the only real effect that's going to come out of a bunch of saber rattling by the President and others is that the American people are going to turn on the news and be de-moralized by the possibility of nuclear missiles falling on America. This negative effect on national morale will be felt coast to coast, and would hinder our national progress.
It's much more rational to continue diplomatic negotiations with the Chinese and North Koreans, and to do so moving toward an understanding in which North Korea would be recognized as a nuclear state.
While our leaders and President struggle with these thorny, life-and-death decisions, we should support them, advise them, and pray for them as well as we can... for they are our democratically elected leaders and hold our lives, and our sacred pact to protect nations like Japan and Switzerland, in their hands. It should be noted, in summation, that former President Carter who has a history of diplomacy with Pyonyang has offered to travel there on a mission of peace.