The American Constitution Society (ACS) is a progressive legal organization. The group's stated mission is to "promote the vitality of the U.S. Constitution and the fundamental values it expresses: individual rights and liberties, genuine equality, access to justice, democracy and the rule of law."ACS was created as a counterweight to, and is modeled after, the Federalist Society, and is often described as its progressive counterpart.Founded in 2001, ACS is headquartered in Washington, D.C. The organization promotes and facilitates discussion and debate of progressive public policy ideas and issues, providing forums for legal scholars, lawmakers, judges, lawyers, public policy advocates, law students, and members of the media. ACS reports that it has approximately 200 law school student chapters and 40 lawyer chapters around the country.On November 14, 2018, the American Constitution Society released a letter signed by over 1,600 attorneys nationwide calling for lawmakers and Justice Department officials to protect the special counsel's Russia probe in light of Matthew Whitaker's appointment as acting attorney general. The signatories call for Whitaker to recuse himself or "otherwise be removed from overseeing the Mueller investigation as a result of his profound ethical conflicts."