Conflict is now joined and the focus shifts to the McCain rejoinder. This will undoubtedly focus on experience, the need for a continuity of foreign policy and the need for entrenchment in view of the economic situation. But will this be enough to counter the challenge which Barack Obama has thrown down? An interesting 10 weeks lie ahead. And of course it will vitally affect what happens in British politics, where the scene focuses on the economic situation and how near recession we are.