In the case of the NATO aerial bombing, the proportional Kosovar deaths can be seen as permissible because these lives were already under threat – if any lives were saved by the bombing, then it was permissible, maybe not morally ideal, but permissible. The lives of Serbian civilians may seem, strangely, to be a tougher case, because these lives were not threatened directly by the Milosevic regime, so they were arguably not under threat already when NATO began its attack. However, Kosovar reprisals had certainly begun to put some Serbian civilian lives under threat, and it is possible that such reprisals would have increased without the NATO bombing. More importantly, the Kosovar people had a right to self-defensive war against the Milosevic regime. To the extent that Serbian civilian casualties were an unavoidable by-product of the exercise of that right to self-defence, then they were regrettable but not morally wrong. If one takes the view that the NATO airstrikes constituted a weapon of self-defence deployed on behalf of the Kosovar people, and that this was the only weapon that was available to the Kosovars (since NATO was unwilling to offer a ground invasion) then the Serbian deaths can be seen as the unfortunate collateral damage caused by the exercise of a Kosovar right of self-defence. The blame for the moral tragedy of the Serbian civilian deaths, like the blame for the moral tragedy in general, lies with the Milosevic regime.