Key congressional leaders say they didn't know President Bush had established a shadow government," moving dozens of senior civilian managers to secret underground locations outside Washington. Senate Majority Leader Thomas A. Daschle (D-S.D.) [said] he had not been informed by the White House about the role, location or even the existence of the shadow government that the administration began to deploy the morning of the Sept. 11 hijackings. Among Congress's GOP leadership, aides to House Speaker J. Dennis Hastert (Ill.), second in line to succeed the president if he became incapacitated, and to Senate Minority Leader Trent Lott (Miss.) said they were not sure whether they knew. Mr. Bush acknowledged yesterday that the administration had taken extensive measures to guarantee "the continuity of government," adding, "This is serious business." Such an operation was conceived as a Cold War precaution against nuclear attack during the Eisenhower administration but never used until now. It went into effect in the first hours after the terror attacks [and] is an extension of a policy that has kept Vice President Dick Cheney in secure, undisclosed locations away from Washington. Cheney has moved in and out of public view as threat levels have fluctuated.