“ A power which has dotted over the surface of the whole globe with her possessions and military posts, whose morning drumbeat, following the sun and keeping company with the hours, circles the earth with one continuous and unbroken strain of the martial airs of England.”
At one time the British Empire was the dominate power on the planet. Vast swaths of Africa, Asia, and North America belonged to the empire, as did all of Australia. The Royal British Navy was the strongest in the world and operated on the “two power standard,” which required that the British Navy be equal to or greater than the combined navies of the next two sea powers. Britain was the first great capitalist power and it made full use of the fact to set itself as the world hegemon, the greatest economic and military power on the planet. Yet today the empire is reduced to a few territories, the United Sates- once a British colony itself- is the world power, and Britain is one of the weaker imperialist countries.
The seeds of this decline were sown in the very rise of the British Empire as the world power in an era when capitalism had not yet fully established itself as the dominate global economic system. Whereas in general colonies held by the imperialist powers were seized after imperialism had developed to such a point that there could be no national democratic revolution in them within the confines of the capitalist system, several British colonies proved the exception to this historical rule. The most prominent example of this is the United States where a ‘mere colony’ of the British Empire underwent its own bourgeois revolution in the form of a national liberation movement and established itself as a capitalist power in its own right. British capitalism also waned in comparison to competing European capitalisms do to its status as a world power; striding atop the world, it tended to stagnation and was heavily invested in technologies that became obsolete. The younger capitalisms of the other Western European powers made widespread use of technology developed after British industry was well established and thereby gained a productive advantage. Germany in particular was the beneficiary of this process and appeared poised to become the dominate power on the European continent.
This German ascendency undermined British foreign policy, which was dependent on maintaining a “balance of power” in Europe, and forced Britain to abandon its role as the arbiter of Europe and develop alliances with France and Tsarist Russia. Germany, one of the last European powers to establish itself, with its increasing domination of continental Europe and hunger for its own colonial empire was an existential threat to the British Empire. Yet in its effort to neutralize this threat, Britain was drawn into the maelstrom of the First World War as one of many imperialist nations and forced to renounce its status as a power among powers, a position that increasingly fell to the United States, which entered WW1 only when the other participants had begun to exhaust themselves and rack up substantial war debts.
The British Empire emerged from WW1 battered, but intact. It was no longer the preeminent world power, but it was still among the first rank of imperialist powers and its German rival appeared to be shattered beyond repair. Colonial independence movements, given new hope by the Bolshevik Revolution of 1917, were beginning to stir, but only a few wild-eyed revolutionists could imagine their triumph and the masters of Europe were not disturbed by them. The Second World War changed all that.
A resurgent Germany, now allied with Italian and Japanese imperialism, sought control of Europe and Africa. Only by allying itself with US imperialism and with the degenerated workers state in the USSR was the Britain capable of protecting the mother country- let alone the far-flung provinces of the Empire. Further, revolutionary movements in European colonies all over the world were coming into their own and efforts to repress them with the crude mechanisms of force and violence were doomed to failure. In these circumstances, Britain was forced to accept the US as the dominate world power and abandon at least the outward trappings of empire. In some cases, such as with the Indian subcontinent, Britain was able to maintain some control of nominally independent nations using the tactics of divide and rule. Yet former British satellites were increasingly drawn into the US orbit or set themselves up as regional powers and only a divided Germany ensured Britain a favored position among the Western European powers.
The end of the Cold War did Britain no favors in this regard. France and a reunited Germany are the dominate powers in Western Europe today, a rising Chinese imperialism is asserting itself in the Pacific and in Africa, and the US remains the world power. Once dominate Britain is now a second or third rank imperialist power, governed by a weak and wobbly “coalition of chaos” that is brought to the brink of collapse at least every other week. At long last, the sun has set on the British Empire.
 The former French colony of Vietnam, which was able to successfully defy not only its former imperial overlords but the full military might of the US as well, is a case in point.