South and North Korea pledged to make peace. If they follow through, that will be a great advance.

Denuclearizing both countries would be a great step forward, too. Maybe someday even India and Pakistan could agree to denuclearize.

We should not presume that final agreement will be reached; there remain many opportunities for things to go wrong. For instance, the bully won't like it, and he may try to wreck it. He does not mind looking like a warmonger.

What has changed is that now there are opportunities for things to go right.