Tony Blair was only mildly optimistic this week as he began his new role as Middle East envoy. I think there is a sense of possibility, Blair said, but whether that sense of possibility can be translated into something, that is something that needs to be worked at and thought about over time. The former British prime minister was appointed by the so-called Middle East QuartetRussia, the U.S., the E.U., and the U.N.to help the Palestinians assemble the economic and political tools they need to build a state. Hes not mandated to discuss the overarching problems that must be resolved, such as borders, refugees, or the status of Jerusalem. Nor is he allowed to meet members of Hamas, the militant Islamist party that won Palestinian elections last year and has since taken over Gaza. As a first step this week, Blair met separately with Israeli and Palestinian leaders and Arab ministers.