The question is now how the world should respond. The most important task for the international community is to establish criminal guilt for this reprehensible act of state-sponsored murder. The Hariri affair must not be co-opted as a political tool by vested interests. Israel is a long-standing enemy of Syria. So too is the US, which accuses Syria of allowing foreign fighters to flood across its borders into Iraq. Both must allow the UN to take the lead in this affair.
Syria has a relatively new president in Bashar Assad. He began by promising reform, but then became bogged down by opposition from the ruling class. It is unlikely to be in the world's interests to undermine President Assad. If the Hariri affair becomes a club with which to indiscriminately beat the Syrian regime, some unpleasant elements could rapidly come to the fore, with dangerous consequences for the entire region.
The investigation must continue and charges should be brought, in time, in the International Criminal Court. The Lebanese Christian leader, Michel Aoun, has called for this. So has Hariri's son, Saad. As we have seen in Serbia, international legal writs can help to instigate regime change from within.
Nothing is likely to happen overnight. But cracks are already starting to appear in the Syrian regime. The Hariri assassination led to widespread anti-Syrian demonstration in Lebanon. Damascus had to order the withdrawal of its 14,000 troops. The "suicide" of the Syrian interior minister, Ghazi Kanaan, earlier this month demonstrated the new vulnerability of the country's formerly all-powerful security apparatus. Syria is also increasingly isolated from other Arab states. The international community can maintain this pressure by continuing to press for justice. That is the sensible way to proceed.