According to current Department of Defense policy, there is no limit to the number of two-, three-, and four-star generals (or admirals) who may be frocked at any one time. However, the number of frocked brigadier generals or rear admirals (lower half) is restricted. Three- and four-star generals are generally frocked if headroom is not available to promote them at the time of the assumption of their new assignment. This is due both to the close relationship between these ranks and the position held, and to the fact that these are considered "positions of importance and responsibility" in accordance with 10 USC § 601. For all other officers frocking is normally reserved for joint, international, or other high-visibility positions that require the higher rank for diplomatic, protocol, or command authority reasons.