Why retaining British Panama would not erase the Monroe Doctrine

If Britain retained Panama and no canal was built, would the United States still adopt the Monroe Doctrine?

The reply expects it to remain, reasoning from memory that the doctrine predates the Panamanian developments imagined in the question.

The question imagines British control of Panama without a canal and asks whether the Monroe Doctrine would still appear. The response places the doctrine earlier than the Panamanian developments under discussion, while explicitly relying on memory for the chronology. It treats the doctrine as an established feature of early nineteenth-century American foreign policy. On that reasoning, the Panama counterfactual would not remove it.