The lack of an agreement between the U.S. and North Korea at Thursday's Hanoi summit, at first glance, appears to have resulted from a lack of flexibility on how to phase sanctions relief and meaningful progress towards DPRK denuclearization.

Absent a joint statement, there is now no clarity on how the two sides can advance the four sets of objectives agreed at 2018's Singapore summit, with likely negative impacts on both the future of both U.S.-DPRK and inter-Korean relations.

While it's too early to tell whether the decision to abandon talks was