Writing at The American Conservative, historian Sumantra Maitra muses about lessons the U.S. can learn from the experiences of the British Empire as he reviews a new book, The Wandering Army: Campaigns that Transformed the British Way of War, by Huw J. Davies. Maitra writes:
The British did not acquire an empire through martial strength alone. It succeeded through realpolitik, the intelligent application of “divide and rule,” and propping up proxies and letting foreign footsoldiers do the bulk of the fighting. These are lessons America still needs to learn.
Time was, every nawab and rajah in India had a British "political" as an adviser. The political was a cross between a diplomat and a military attache with espionage on the side. As I understand it, politicals gave no orders but their advice was often followed.
The one time we did follow this path, when we helped the mujaheddin kick the Soviets out of Afghanistan, it worked very well and cost us relatively little.