Leading article: The West must act quickly to save Libya from Gaddafi

Iraq, the Balkans, Zimbabwe and now Libya.

Once again the world faces the dilemma: how to halt a ruthless tyrant, entrenched in power for decades, who is slaughtering his own people to survive. Some might say this is an internal Libyan matter, in which outsiders should not intervene. But our own self-interest as well as basic humanitarian arguments demand that we act, at once. So what should be done – and by whom?

In an ideal universe, the United Nations Security Council would lead the way with swift and comprehensive sanctions that would remain in place until the Gaddafi regime was gone. But the nature of the UN beast makes that unlikely. In practice, it is up to the major Western powers: the US of course – but in equal measure Europe, even more directly affected by the unfolding chaos on the southern edge of the Mediterranean.

Some steps are self-evident. They include a freeze on assets held abroad by Gaddafi and his henchmen, a ban on foreign travel, and steps to exclude Libya from the global financial system. Europe, the most obvious destination for many Libyan refugees, must be prepared to receive them temporarily, and help to establish sanctuaries inside Libya, or across the Egyptian and Tunisian borders. The US is further from the scene of Gaddafi's crimes, but with its massive intelligence and national security resources, can play a vital part.

What is essential is that the major powers act as one, immediately and unequivocally. They must not only spell out in unmistakable terms that the actions already taken by the regime are unacceptable. They must explicitly demand regime change, and declare that the current government has committed crimes against humanity that will be punished in the International Criminal Court.

This is not simply the least that the brave opponents of an odious tyrant deserve. By now Gaddafi and his diehard allies are surely too stained with blood to do anything but continue with repression. If this dictator is toppled, the niceties of the ICC, one suspects, will prove superfluous; far more likely is summary justice of the kind meted out to Mussolini or Ceausescu. But that is for later. The sterner the words now from the West, the more likely that others around Gaddafi might be persuaded to defect, bringing closer the regime's downfall, and reducing the loss of life.

The last option is direct military intervention. The precedents are mixed. The US-led 2003 invasion of Iraq proved to be a disaster. More promising is the Kosovo model of 1999, where aerial bombardment by Nato broke Milosevic's grip on Serbia's breakaway province. But a repeat would risk making the Western powers the arbiters of Libyan internal politics, post-Gaddafi. The Iraq experience suggests that would not be a happy process. At the very least, however, the US, Britain, France and other involved powers such as Italy should swiftly impose a no-fly zone, of the kind used pre-2003 to protect the Iraqi Kurds and the Marsh Arabs from the depredations of Saddam Hussein, with considerable success.

What matters most is speed. This is no time to worry about Libyan oil, or the nature of the regime that will follow. The longer Europe and the US dither, the more lives will be lost.