"Administrative subpoena authority is the power vested in various administrative agencies to compel testimony or the production of documents or both in aid of the agencies' performance of their duties. Both the President and Members of Congress have called for statutory adjustments relating to the use of administrative subpoenas in criminal investigations. One lower federal court has found the sweeping gag orders and lack of judicial review that mark one of the national security letter practices constitutionally defective. Proponents of expanded use emphasize the effectiveness of administrative subpoenas as an investigative tool and question the logic of its availability in drug and health care fraud cases but not in terrorism cases. Critics suggest that it is little more than a constitutionally suspect 'trophy' power, easily abused and of little legitimate use. Proposals in the 109th Congress for greater use of administrative subpoenas in a law enforcement context appear in S. 600, relating to the Secretary of State's responsibilities to protect U.S. foreign missions and foreign dignitaries visiting this country; in H.R. 3726, relating to federal obscenity investigations; and in H.R. 4170, relating to the apprehension of fugitives charged with, or convicted of, federal or state felonies."
CRS Report for Congress, RS22407
Federation of American Scientists: http://www.fas.org/main/home.jsp