Impermissibility of Deputizing the House Sergeant at Arms as a Special Deputy U.S. Marshal: Memorandum for the Deputy Attorney General [April 10, 1995] [open pdf - 22KB]
"You have asked our opinion whether there is any constitutional impediment to the deputation of the Sergeant at Arms of the House of Representatives ('HSA') as a Special Deputy United States Marshal ('DUSM'). Given the nature of the HSA's status and statutory duties as an Officer of the House -- which include maintaining order in the House under the direction of the Speaker -- it would be virtually impossible to separate or segregate those duties from the law enforcement duties of a DUSM, giving rise to inherent conflicts in accountability between the two positions. Consequently, we conclude that the proposed arrangement would raise serious concerns under the constitutional separation of powers."
United States. Department of Justice: http://www.justice.gov/