Presidential candidate Donald Trump is standing behind his proposal to prevent Muslims from entering the United States. While he says it would be a temporary prohibition, he cites a precedent for it — FDR's proclamation against some immigration during World War II. Trump told CNN Tuesday the nation faces "many more World Trade Centers" if its leaders don't take action against Islamic terrorists, many of whom are already in the country. While he provided few details and wouldn't say how long such a ban would last, he faulted President Barack Obama for not declaring that the U.S. is "at war...