WASHINGTON -- The creation of a military command whose sole mission is to defend American territory will not erode legal limits on using federal troops inside U.S. borders, Defense Secretary Donald H. Rumsfeld said Wednesday.

The central change to the military's command structure will be establishment of a Northern Command, probably with headquarters at Peterson Air Force Base, Colo., to centralize the military's role in defense of the United States.

The main impetus was the Sept. 11 attacks, which demonstrated that the military was not set up to deal with unconventional attacks from inside the country. Since the attacks, the military has flown daily air patrols and has placed more fighters on ground alert.

The creation of Northern Command will not conflict with a 19th century law, called the Posse Comitatus Act, that was meant to prohibit the military from acting as a domestic police force, Rumsfeld said in announcing the changes.

"Some in the past have worried that creation of a command that covered the United States of America could be inward-looking; nothing could be further from the truth," Rumsfeld told a Pentagon news conference.

"The creation of NorthCom means that we now have the command assigned to defend the American people where they live and work and it will be functioning in a supporting role to civil authorities as occasions arise," he said.

If, for example, a federal, state or local law enforcement agency needed help in responding to a terrorist threat or attack in an American city, its request would go to the commander of Northern Command through the Defense Department. The forces provided by Northern Command for that mission would be subordinate to civil authorities, Rumsfeld said.

Gen. Richard Myers, who as chairman of the Joint Chiefs of Staff was a key architect of the command changes, said at the news conference with Rumsfeld that decisions have yet to be made on which U.S.-based forces will be placed under the control of Northern Command.

Also undecided is whether a U.S. missile defense system, possibly based in Alaska, would be under Northern Command's control.

Rumsfeld said no officer has been nominated as commander of the Northern Command. Other officials said privately that President Bush is expected to nominate Air Force Gen. Ralph Eberhart.

Eberhart is commander of both the North American Aerospace Defense Command, or NORAD -- in charge of defending U.S. and Canadian airspace -- and Space Command, which is responsible for defending U.S. interests in space. If he became commander of Northern Command, he would retain his role with NORAD but would no longer be commander of Space Command, officials said.

Rumsfeld said the command structure changes are meant to help the military operate in an "era of the unexpected."

"We must be ready to win today's global war on terror, but, at the same time, prepare for other surprises and uncertainties that we must will most certainly face in the 21st century," he said.

------

On the Net:

New command plan: http://www.defenselink.mil/news/Apr2002/g020417-D-6570.html

Posse Comitatus Act: http://law.wustl.edu/WULQ/75-2/752-10.html