UN mandate is a start, but it's not over yet
The United Nations' Security Council Resolution on Libya is one thing, but how it will work out in practice is another matter.
While preparations are continuing for international military measures against the murderous Colonel Gaddafi and his forces, many details of a possible UN intervention remain unclear.
The Security Council Resolution went much further than condoning a "no-fly zone" and it gave broad backing for military action against all threats to civilians in Libya short of occupying the country.
The UN has taken its time to act, but the world has at last mustered enough support for concerted action against Gaddafi, despite the abstention of powers such as Russia and China.
However, the UN Resolution has created a tricky situation where no-one is clear about what action will be taken in the short-term, and who will take it.
Amid such uncertainty, extreme caution is needed. Even at this late stage, diplomacy and sanctions, as well as the threat of imminent military action, may still have an important part to play in the swiftly changing situation in Libya.
Gaddafi is ruthless and clever, and his announcement of a ceasefire just after the UN Resolution will fool no-one. The Libyan government is capable of extreme measures at local level, despite the UN Resolution.
Major partners in the global community, including Britain, cannot stand idly by, and the UN Resolution shows that they are not prepared to do so.
Yet any intervention may drag Britain and her allies into a conflict where disengagement becomes extraordinarily difficult.
Recent history in Iraq is a chilling example of what can go wrong even when nations act with the good intention of helping oppressed peoples.
These are difficult times and, while many are sympathetic to the Libyans under Gaddafi's brutal rule, Britain and other countries cannot write a blank cheque in blood and untold commitment. The UN Security Council has provided a vital mandate for international action, but deep unease about the way ahead in Libya remains.