ONLY A FEW years ago, it seemed the slightest suggestion of malfea- sance by a presidential administration -- allegations of tampering with a minor administrative office, say, or indications that a cabinet secretary might have understated the amount of money given to a former girlfriend -- could trigger a formidable response from the other two branches of government: grand juries, special prosecutors, endless congressional hearings, even impeachment proceedings. Some of that auditing, especially during the Clinton administration, went too far. Yet now the country faces a frightening inversion of the problem. Though there is strong evidence of faulty and even criminal behavior by senior military commanders and members of President Bush's cabinet in the handling of foreign detainees, neither Congress nor the justice system is taking adequate steps to hold those officials accountable. Investigations by the Army, including one completed last week, could result in prosecution or disciplinary action for up to 50 persons involved in the abuse of Iraqi prisoners. But almost all are low-ranking soldiers; the most senior officer to be targeted is a female reserve brigadier general, who plausibly argues she has been scapegoated by higher-ranking officers. The military investigations and a separate probe by a panel picked by Defense Secretary Donald H. Rumsfeld have issued reports making it clear that senior commanders in Iraq and the civilian leadership at the Pentagon also bear specific responsibility for an affair that has gravely damaged the U.S. mission in Iraq and American prestige around the world. But no court, prosecutor or disciplinary panel is even considering action against these top officials. Only one more congressional hearing, by the Senate Armed Services Committee, is planned.