Egypt's allies face a diabolical set of choices. How to respond when confronted with mass calls for democracy from the streets, a long-time friend under threat, and the risk of anarchy that, once unleashed, could spread across the whole region?
The answer, such as it is, has been a day-to-day shift from support for stability at all costs to tentative acceptance of the need for change and, by Tuesday, to backing for a smooth transition – in other words, an end to Mubarak's rule. No less striking has been the general hands-off restraint, in public at least, from the US and others, and the consistency of the language at each stage.
It is tempting to speculate that the same instant communications that aided the Egyptian protesters until the internet was curtailed have helped foreign leaders to present a co-ordinated front.
International organisations are often chided for being ineffectual but, two years ago, at the height of the financial crisis, the big central banks and the G20 showed an impressive degree of co-ordination. Twenty years ago, with slower-moving communications, a similar display of Western solidarity helped minimise the damage as the Soviet Union collapsed. The same thing seems to be happening here.
It is as though, when they feel the chips are really down, those leaders with most at stake manage to summon up a common sense of urgency and responsibility. The mood percolated even the Cameron-Miliband exchanges about Egypt at yesterday's otherwise tetchy Prime Minister's Questions.
Day by day, it is as though one message has been agreed – to be conveyed by whichever leader has a platform: do not interfere overtly; do nothing to assist, nor to humiliate, superannuated autocrats; do not, in any circumstance, undermine grassroots calls for democracy. Maybe it is because the similarity between individual Western interests in Egypt is so great that so little friction can be detected.
It seems rather that everyone has judged the situation too dangerous to indulge in diplomatic games. The only doubt must be whether, if security in Egypt deteriorates, this unity of message can be maintained..