We know the DPRK possesses VX nerve agent, the most potent of the known chemical warfare agents, which is "as persistent as motor oil," so a North Korean chemical attack would make large parts of South Korea uninhabitable for quite some time. South Korea's defense ministry estimated in 2014 that the DPRK has somewhere between 2,500 and 5,000 tons of nerve agents in stock and ready for use.
"Trump's attack on Syria is unlikely to have any significant effect on a North Korea that is already well versed in the threat posed by the United States," said Joel Wit, a senior fellow at the US-Korea Institute at Johns Hopkins University.
The targeting and killing of Kim Jong-un was also mentioned by the NSC, but this is problematic because our intelligence on his whereabouts is lacking. Perhaps we could convince someone in his inner circle that we would give his family a substantial sum of money if he wore a GPS tracking device and switched it on in Kim's presence. Or better yet, we could surreptitiously inject a tracking device into the body of Dennis Rodman -- he'd never even notice it, given the large amount of metal already embedded in his body -- and kill two ugly birds with one stone after he made one final trip to visit the marshal.
The U.S. has sent the USS Carl Vinson strike group to the area, but perhaps we should worry about China's DF-21D hypersonic missiles which have around twice the range of any of our carrier aircraft. so any carrier would need to loiter well within range of China's missiles. It would be a real shock to discover that China lent the DPRK a few of them. Sure, aircraft can refuel, but tankers would be sitting ducks, so maybe it would be a one-way trip, not to mention China's Su-35, which has a range well in excess of 2000 miles.
If the U.S. really intends to destroy the DPRK's military, the 10,000-20,000 artillery pieces must be destroyed in the first minutes of the attack. All of the entrances to their reinforced bunkers were repositioned to face the north, so it might be necessary to attack them using Tomahawk cruise missiles aimed at the heavy steel doors.
Aircraft-delivered bunker buster bombs would be an alternative, but the skies over North Korea might be less hospitable than the skies over Iraq were. Perhaps North Korea paid rapt attention to how a missile battery commanded by Serbian Colonel Zoltan Dani shot-down an F-117, while NATO forces were never able to shut-down his missile batteries. And in Desert Storm, Iraqis noticed F-117s refueling and launched an attack on them assuming they would continue to Baghdad, though luckily the F-117s were actually going to Mosul. The F-22 could play a role, but given its paltry combat radius of 529 miles, it might need to operate from nearby airfields, an option which might not be available after North Korea sends a few artillery shells loaded with chemical munitions their way.
We used 1000 Tomahawks in both Iraq wars combined and there was no threat from artillery situated in bunkers. We'd better ramp up production of Tomahawks -- in 2015, we only had around 3500 -- and Raytheon has only delivered some 3,000 of the latest variant, the Block IV, since its introduction in 2004. Tomahawk Block IVs have the same range as China's DF-21D, so we might want to improve that in the near future. And the USS Ross, one of the destroyers to take part in the Syria attack, can only carry 90 Tomahawks, so we'll need lots of ships.