The State of Oregon went through a similar situation in 2008. Justia.com was mirroring the Oregon Revised Statutes, and was served a cease & desist—not because the State claimed copyright over the laws themselves, but rather over the metadata such as indices, tables, line numbers, etc. In the end, the State agreed not to assert copyright over the laws (though that does not equal an admission that they do not have copyright). More: https://public.resource.org/oregon.gov/index.html#trail