Of all the ministers, princes, party leaders and diplomats I worked with as Foreign Secretary, America’s Secretaries of State tended to be the most impressive. Hillary Clinton and John Kerry were entirely different from each other in their working habits but both enormously impressive in their energy, ideas and intellectual grasp. Of course, they had the advantage of a vast machine working for them, but the world is sadly full of people who have dozens of aides and are still not up to their job.