A fundamental principle of the rule of law is fairness. Among other considerations this means that people who have been subject to due process and no case has been proven against them should be left alone, not continually pursued.

Yet these protections appear to have been cast aside where members of the Armed Forces who served in Iraq are concerned. Major Robert Campbell, a decorated officer, is facing his eighth official investigation regarding the death of an Iraqi in 2003.

He was cleared of manslaughter 12 years ago, but the case was then taken up by human rights lawyers and has since triggered several official inquiries, the latest by the government-financed Iraq Fatality Investigations (IFI)....