Jeffrey Rosen, who served as acting attorney general in the waning days of the Trump administration, is joining the conservative think tank American Enterprise Institute as a nonresident fellow.

Rosen will focus on administrative law and regulation, constitutionalism and legal institutions. His work will be part of AEI’s new Center for American Constitutional Governance, which aims to “restore the integrity and order of the American constitutional system, with an emphasis on the proper roles of Congress, the executive and the courts; a renewal of federalism; and a rekindled understanding of citizenship, civil society and republican virtue,” according to a news release from the institute.