Britain and America had already agreed a joint policy of dealing with ‘Germany First’, before Japan. The actual means of achieving this goal were more contentious. Some very tough characters on both sides of the Alliance were now arguing out the details. The Chief of the Imperial General Staff, General Sir Alan Brooke was to record in his diary the fractious start to the proceedings on 20th July 1942:
Arrived WO [War Office] 9am. Found mass of messages. Troublesome COS [Chiefs of Staff meeting] with Mountbatten [now Head of Combined Operations] again assuming wild powers unto himself!
At 12.30 we went round to 12 Downing Street to meet American Chiefs of Staff with PM! We had originally intended to meet them at 10 am ‘off the record’ for a private talk, but PM very suspicious and had informed me at Chequers that Marshall trying to assume powers of C-in-C of American troops which was (constitutionally) President’s prerogative!
After lunch at 3 pm we met [General] Marshall and [Admiral] King and had long argument with them. Found both of them still hankering after an attack across Channel this year to take pressure off Russia. They failed to realize that such an action could only lead to the loss of some 6 divisions without achieving any results!
Next argument was that we should take advantage of German preoccupation with Russia to establish bridgehead [in France] for 1943 operation. Had to convince them that there was no hope of such a bridgehead surviving the winter. Next discussed altemative operations in North Africa which they are not much in favour of preferring the Pacific.