George Bush - under enormous political pressure at home - needs to ensure that his voters cannot say that now even the Brits are deserting him. He will know what it is that his visitor needs to go home happy and he will want to deliver it.Nick Robinson seems to think that the rebranded trans-Atlantic alliance might finally bring about decisive and long overdue action in Sudan. Much as I would love to believe it, with the likes of China and the EU still making "more time for diplomacy," I can't see the Brown-Bush summit being that successful.
Key to that is a war - not the one which Britain and America started but one which they hope to help stop - the war in Darfur. Both men are backing a UN resolution this week which will not merely establish a 19,000 strong peacekeeping force in Darfur and will not only back a peace process between the warring factions but will also offer Sudan a package of long term economic support if it agrees to co-operate - a carrot to accompany the sanctions stick.
For Gordon Brown this would prove that something can be done to tackle what he calls the greatest humanitarian crisis the world faces. For George Bush it would prove that America is willing to act on the world stage to build and not just to destroy.