State sovereignty is not a licence to kill. No state can abdicate the responsibility to protect its people from crimes against humanity, let alone justify perpetrating such crimes itself. When it manifestly fails in that protection, it is the responsibility of the international community to provide it, if necessary – should peaceful means be inadequate – by taking timely and decisive collective action through the United Nations Security Council.

This is the “responsibility to protect” principle embraced unanimously by the General Assembly in 2005. There is no clearer case for its application than the dire situation unfolding in Libya. Muammer Gaddafi’s forces have already massacred perhaps more than a thousand of his own people, protesting (initially peacefully) against the excesses of his regime. A bigger bloodbath seems inescapable if he does not step down. The need for decisive action is overwhelming.

The Security Council, after moving with painful caution in the first few days of the crisis, has over the weekend invoked the responsibility to protect principle and – in a historic first – agreed on a substantial package of measures to implement it: an arms embargo, asset freeze, travel bans and, importantly, reference of the situation to the International Criminal Court.