Democratic lawmakers are disputing the legality of Chad Wolf's appointment as acting Homeland Security secretary and immigration hardliner Ken Cuccinelli as his deputy, asking the U.S. Comptroller General for an expedited review.

Why it matters: If the argument set forth by two House committee chairs on Friday prevails, it could give Democrats a path to try to block the ascension of Cuccinelli, or more broadly to seek to invalidate months of agency actions.

Between the lines: Before leaving office, former DHS Secretary Kirstjen Nielsen changed an internal policy determining who is next in line if the current agency head can no longer serve in that position.