By Maayan Lubell TEL AVIV, July 8 (Reuters) - Rahm Emanuel, a Democrat weighing a 2028 U.S. presidential run, said on Wednesday that Israel risks jeopardizing its alliance with Washington unless it changes course on the Palestinians because of growing unease with its policies among U.S. voters. A former Chicago mayor and chief of staff to former President Barack Obama, Emanuel used a speech at Tel Aviv University to criticize Prime Minister Benjamin Netanyahu's government and propose a new U.S.