DENVER – The agreement on Syria’s chemical weapons reached by Russia and the United States is important not so much for what it could mean on the ground – which remains to be seen as inspectors begin to flow into Syria and, we hope, chemical-weapons stockpiles begin to be destroyed. Rather, the agreement’s main significance consists in the fact that it was struck at all: US Secretary of State John Kerry met with his Russian counterpart, Sergei Lavrov, in Geneva, that most traditional of diplomatic venues, and cut a deal on an issue of intense mutual interest.