A federal judge temporarily blocked Florida’s new law that requires welfare applicants to pass a drug test before receiving benefits on Monday, saying it may violate the Constitution’s ban on unreasonable searches and seizures. Judge Mary Scriven ruled in response to a lawsuit filed on behalf of a 35-year-old Navy veteran and single father who sought the benefits while finishing his college degree, but refused to take the test. The judge said there was a good chance plaintiff Luis Lebron would succeed in his challenge to the law based on the Fourth Amendment, which protects individuals from being unfairly searched.