The summit between North Korea's Kim Jong-un and the South's Moon Jae-in was rich in symbolism and breathtaking in its dramatics. The two leaders — who just months ago were preparing for possible war — held hands, crossed into each other's territory, posed for photos and joked together. They also made commitments that, if fulfilled, would represent a huge step toward peace on the peninsula.

Yes, but: Much turns, however, on whether those commitments are indeed fulfilled. Seoul and Pyongyang agreed to “complete denuclearization” of the peninsula and to pursue a peace treaty that would officially end the Korean War. Yet the pledges included no timeline for the North's denuclearization, no process for verifying steps toward it nor a plan for how Kim would detail his nuclear and missile arsenals.