In the past, The United States government has taken comfort in the position that North Korea did not possess a significant nuclear weapons program, however it is no longer the case that North Korea does not possess nuclear weapons. Upon taking office, the Obama administration may arguably have relied on North Korea not having a viable nuclear weapons program, but upon taking office the Trump administration totally lacks that luxury.
What was named as being unacceptable has now clearly come to be an accomplished fact. Engagement, diplomacy and sanctions failed to prevent the development of a North Korean nuclear weapons program.
North Korea has tested nuclear devices in the 10 to 15 kiloton range; North Korea knows what must be done to make these devices work and there is nothing in particular to prevent North Korea from manufacturing many more such devices---they have adequate supplies of fissile material to do so it seems. Whereas now it seems North Korea possesses perhaps ten nuclear weapons, perhaps in 10 years North Korea may have hundreds of such weapons in their arsenal.
There is much discussion about whether North Korea has the ability to place a nuclear warhead on a missile and hit a distant target. If North Korea does not have this ability, then they are working on it. At any rate, it is not really required for a missile to be the agent to deliver a nuclear warhead; nor is it certain that North Korea would not be willing to transfer a nuclear warhead to another entity than itself under some circumstances.
The North Korean regime openly declares its intent to make many more nuclear weapons, and openly declares its willingness to use these weapons. There is a tendency from some quarters to not take these threats seriously, but when such threats are made repeatedly, as they repeatedly have been made, due consideration should be given to the possibility that these threats may be acted out by the North Korean regime. Much is made of the Kim regime not actually attacking with nuclear weapons since that is supposed to be something that would end their regime, but that imparts a pattern of thought on the Kim regime that may not actually exist. The Kim regime may believe that The United States will not really forfeit cities in The United States in retaliation for a disabling strike with nuclear weapons against South Korea---I am not so sure South Korea actually believes that either, and I am not so sure even I really believe that either. I do believe that the Kim regime believes the Kim regime should control South Korea.
The Obama administration and others in the government of the United States made a choice not to use military force to destroy the ability of North Korea to make nuclear weapons, and now to do so would be much more dangerous. The Kim regime it seems is of the opinion that no one will do what is necessary to prevent the North Korean manufacture of nuclear weapons and delivery systems for those weapons.
So...it would seem that a North Korean nuclear weapons program IS acceptable after all. After all, the existence of a North Korean nuclear weapons program is an accomplished fact.