People who signed the letter said they were driven by a sense of national responsibility and concern that the troop presence endangered Jordanian sovereignty. Hundreds of Jordanian political, legal and other figures signed an open letter last week calling for the withdrawal of U.S. forces from Jordan in a rare public challenge to the government, which has long cracked down on free speech and dissent. Last year, the United States gave Jordan $1.65 billion in economic and military assistance, according to Jordanian officials. Since the letter was released, al-Tell said, hundreds more Jordanians have added their names to it, despite knowing the risks. Jordanian security forces also raided the headquarters of Jordan’s largest opposition party, the Islamic Action Front, considered the political arm of the Muslim Brotherhood in Jordan.