By Allyn Fisher-Ilan JERUSALEM (Reuters) - The Palestinians could lose annual U.S. aid if they file a lawsuit against Israel at the International Criminal Court which they joined this month over American and Israeli protests, a senior U.S. Republican senator said on Monday. Lindsey Graham, part of a seven-member delegation of senators visiting Israel, Saudi Arabia and Qatar, said existing U.S. legislation "would cut off aid to the Palestinians if they filed a complaint" against Israel. At a news conference in Jerusalem, Graham called the Palestinian step "a bastardising of the role of the ICC.