[mugs99]

The United States has merely supplanted Britain as the leading power

That was the result of the Spanish/American war. We have been number one since then.
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[jpl]

That was the result of the Spanish/American war. We have been number one since then.

I would argue that Britain was still a superior overall power to the United States right up to WWI, which wore down the British Empire greatly, and then the WWII Axis killed off its remnants.