Massimo Calabresi in today’s Time.com gets at what it means:
In one way, the message is simple: Ross, a career foreign service officer, was lead negotiator on Israeli-Palestinian issues for Presidents George H. W. Bush and Bill Clinton, and he got the two sides as close as they’ve come to a peace deal before stepping down after the 2000 election. His presence alongside Obama in Israel, the Palestinian territories and Jordan is designed to signal the senator’s intent to resume the active pursuit of the peace process, which Obama claims President George W. Bush has derailed through inaction. . . . Still, it is somewhat surprising to see Ross emerge as an official member of Obama’s team. . . . When Ross left the State department in 2000, he was so critical of Yasser Arafat, that some friends thought he was considering working for George W. Bush, who cut ties with the late Palestinian leader. “At the beginning of the Administration he hadn’t excluded the possibility of working for a Republican again,” says one. Ross supported the Iraq war, though he opposed some of the Bush administration’s policies for post-war reconstruction.