American and British Cooperation is a reoccurring idea in the book.
The 1950s ushered in the decline of the British Empire and the rise of The Unites States as a dominant world power. As this happens both countries create a special relationship that is reflected in the cooperation between Bond and Leiter. There is a rivalry there but primarily they work very well together and see themselves as having the same end goals. At this time especially they are fighting a common enemy in the Soviet Union represented by SMERSH.