A significant sequence of events is unfolding in Westminster, which seems set to isolate Jeremy Corbyn, and bring the DUP centre stage.
As David Cameron joins the French president Francois Hollande in Paris today to discuss the international crisis, there is a clear move towards a role for British forces in tackling the Isis barbarians.
The massacres opened the eyes of many people in the world who had hitherto failed to grasp the savagery that was emerging in the Middle East, and the wider threat it posed. Now there is a unanimous UN security council resolution.
The Labour Party leader has been humiliated by events, and his reluctance to endorse even elementary security responses such as shooting dead terrorists who are about to launch such an attack.
One by one, members of his shadow cabinet publicly repudiated his naivete, as they did one by one when he said that he would not be prepared to use the nuclear deterrent if he was prime minister – ensuring that it had no deterrence value.
This is unprecedented. In extraordinary scenes last week, Mr Corbyn was also isolated by his colleagues in the Commons chamber, either by overtly siding with Mr Cameron or by leaving the Labour leader alone on the benches.
It is unclear how senior Labour Party figures will respond when the prime minister presents his case for escalating British military involvement when he responds to a Foreign Affairs Committee report this week. But the party will not want to appear weak on security after the horror of Paris.
While Mr Cameron will probably suffer rebellion from a number of backbench Tories, the DUP is signalling that it is open to supporting action. Given that some Labour MPs will almost certainly back government proposals, it becomes likely that they will pass, whenever a vote comes. That will be good for Britain’s reputation and for unionists, who will emerge with enhanced influence at Parliament.