Mr. Rumsfeld supported the office's broad mandate to integrate the Pentagon's information warfare machinery with other federal agencies. But top aides said he never approved any of the specific proposals that raised opposition.

''What it was to do was an open question, even today as it ends its very short, prominent life,'' Mr. Rumsfeld said.

Until the disclosures, little was known about the office. Its multimillion-dollar budget, from a $10 billion emergency supplement to the Pentagon's budget authorized by Congress in October, has not been disclosed. Congressional aides said the office had discussed financing perhaps as much as $100 million in activities, many through other agencies, like the State Department, that have limited budgets for information warfare.

Pentagon officials said Mr. Rumsfeld was upset that the internal debate over the new office had become public. Today, even military officials who said they were happy to see the office closed said they were afraid the damage had already been done.

''It makes us all look bad,'' said one public affairs official. ''Every day now reporters ask me if I've lied to them.''

Other senior officials said they had barely been aware of the new office and had not realized the implications of its activities until the debate broke into public view last week.

''If I had known about this earlier, I would have gone to him and recommended he kill it,'' one adviser to Mr. Rumsfeld said. ''You don't want things like O.S.I. in the Pentagon. It elevates that kind of work to a level you don't want.''