Civil rights and immigrant support groups have filed an appeal against a federal judge's refusal to block key parts of Alabama's tough new immigration law, regarded as the most draconian in the country. "The bottom line is it [the ruling] effectively criminalizes undocumented illegal persons in the U.S.," said Peter Spiro, an immigration law expert at Temple's Beasley School of Law. "If they start enforcing this, the consequences would be dramatic; there would be a mass exodus in Alabama of undocumented aliens. The question mark is, there's a lot of discretion to enforce laws."