In all first transatlantic encounters there is form and then there is substance. In form, David Cameron and Barack Obama seemed strikingly well-matched: of similar height, with similar charm, and both left-handed. (When was that last true of a British and a US leader?) And the diplomats had devised the sort of little trick that smoothes along even potentially prickly meetings. Remember Tony Blair and George Bush at a wintry Camp David and a shared taste for Colgate toothpaste? This Prime Minister and this President went one better. They had supposedly bet each other a couple of bottles of their local brew on the result of the England-USA World Cup match. As it was a draw, each had brought his own.
Mr Obama also appeared to have taken instruction in British political sensitivities since his somewhat chilly first meeting with Gordon Brown. The key to getting off to a good start, he now realises, is to pepper the conversation with mentions of the "special relationship". It costs nothing, and it makes a British leader feel wanted. All in all, the form was nigh-perfect in every respect.
As for the substance, two circumstances boosted Mr Cameron more than he could possibly have expected. The first was the precipitate downfall of General McChrystal, the US commander in Afghanistan. Here was proof that all was not well with the US campaign in Afghanistan and this opened the way for an exchange that presupposed – on both sides – the desirability of an early exit. This had also been the mood of the G8 summit that preceded their meeting.
The second is the ease with which Mr Cameron, despite his Eurosceptic tendencies, has found himself fitting into a European consensus on the economy. His coalition with the Europhile Liberal Democrats, led by the multilingual Nick Clegg, and his decision to visit Paris, Berlin and Brussels before setting out across the Atlantic, struck an early positive note in the EU. But the emergency Budget has also placed Britain closer to Berlin than to Washington in the deficit-cutting versus fiscal-stimulus debate and allies are useful to have.
By this morning some, if not most, of the differences in economic approach may have been ironed out in the documents agreed by the G20. There is likely, though, to be more form here than substance. In bilateral relations on the other hand, Mr Cameron may return satisfied that on the two most salient questions preoccupying our two countries – Afghanistan and the economy – there is now the prospect of a real discussion.