As @potus @realDonaldTrump @StateDept tries to walk, chew gum, and ingest bleach at same time, they must contend with possibility that Kim Jong-un, leader of DPRK, may be incapacitated or even dead. DPRK probably has enough fissile material for 30-50 nuclear weapons. What to do?

Let me offer up some suggestions, as one who had to help puzzle out DPRK policy at State Dept and Senate Foreign Relations Committee from 1989-2012.
Do:
1) Coordinate all steps with ROK, and keep Japan and China in the loop. This is vitally important. Don't "go it alone."

Do (if death or incapacitation is confirmed):
2) Extend our condolences “to the people of the DPRK upon hearing the news of the death of Kim Jong-Un.” Keep it simple.
3) Reiterate USA commitment to the Singapore 2018 Joint Statement. Specifically....

4) express hope that, "Government of DPRK will work with USA and ROK to fulfill the commitment of Kim Jong-un to build a lasting and stable peace regime on the Korean Peninsula and to work without delay toward the complete denuclearization of the Korean Peninsula."

Do:
5) PRIVATELY remind DPRK leadership that the security of that country’s nuclear and missile assets -- i.e. preventing any use or transfer of those assets -- is a matter of "grave concern" to the United States. We will act decisively, if necessary, to protect our security.

Do:
6) Reiterate offer by USA to work w/DPRK to address humanitarian needs created by COVID-19 pandemic on strictly humanitarian basis, without political conditions.
7) quietly intensify intel gathering. Focus on non-proliferation threat; export of nuclear material or expertise

What should we AVOID doing? What items are on the "Don't Do" list?
DON'T:
1) Say or do anything that could be construed as threatening DPRK — e.g. no military alerts or maneuvers, no force augmentations, no destabilization or propaganda efforts.

These next couple of recs are going to be VERY hard for Trump to abide:
2) Don't praise KJU as a "good guy" or as "my good friend." He is NEITHER.
3) Don't lionize Kim or speak of “special relationship” between Trump and Kim. Don’t personalize this. If anything, keep distance

Finally -- Don't:
4) Celebrate this as a chance for DPRK “to move in a ‘new’ direction.”
We want DPRK to do what it promised in Singapore. If we are very fortunate, a new leadership MIGHT be more willing than Kim to do that (although I very much doubt it). But....

...if we want them to change course and be more forthcoming on peace and denuclearization, they must get there under their own steam, not as a result of a heavy-handed pressure campaign mounted on a new leadership in time of crisis.

In all likelihood, DPRK will go turtle for months if Kim Jong-un perishes. Any new leader will need time to consolidate their position before engaging the international community.

There are a couple of other things we SHOULD be doing in light of KJU disappearance from view.

We should swiftly conclude negotiations with ROK on our forces and their contribution to their upkeep. This is a no-brainer, and we make ourselves vulnerable by prolonging the talks.
We should also drop the blame game with China on COVID. China holds much sway over events...

...on the Peninsula, and probably has the best overall window (intelligence, and special relationships) into the DPRK leadership. We need to be working with Beijing, not against them, when it comes to peace and stability on the Korean Peninsula.

Finally, let me say that managing uncertainty is one of many reasons why @potus @VP were WRONG to stiff Kim Yo-jong at 2018 Olympics. Had Pence shown even basic human courtesy toward her, we could today be in a stronger position. Pettiness & Rudeness are not assets in diplomacy.

For great info on DPRK, check out @38NorthNK where scholars who have great expertise routinely contribute articles on all aspects of the challenge posed by North Korea. For great spy-thriller novels on DPRK, check out @readjameschurch