And that is true for the U.S. today. We could meet our domestic fossil fuel energy needs, but we find economic advantage in trading energy anyway. But when we want to use energy as a tool of policy, we have the option.
This happens in personal finance too. I can pay off my mortgage: I have enough capital to do so. So I don’t fear the bank. But with mortgage interest rates so low, I’ve found comparative advantage by keeping my mortgage and investing my capital elsewhere.