RAMALLAH, West Bank — A small crowd of Palestinian protesters accosted an American diplomatic delegation visiting the West Bank Tuesday, blocking a convoy of vehicles, chanting “shame on you” and hurling a shoe — a deeply insulting gesture in Arab culture. The Americans, including employees of the consulate in Jerusalem, were on their way to a U.S. reception in town of Ramallah meant to reaffirm cultural and educational ties with the Palestinians. But relations have grown strained recently, with Palestinians disappointed over President Barack Obama’s handling of Mideast peace efforts. They say he is not tough enough on Israel and...