TALLAHASSEE, Florida (Reuters) - A new Florida law that requires low-income parents to pass drug tests before receiving public aid constitutes an illegal search, the American Civil Liberties Union of Florida said Wednesday after suing to block it. By mandating tests for people who are not suspected of drug use, the law violates the constitutional ban on unreasonable searches and seizures, ACLU representatives and a 35-year-old Navy veteran who refused to take the test said in a conference call with journalists.