In "The Second Coming," where is there an example of how the allure of power causes people to behave in unethical ways?
I think that the issue of a lack of ethical guidance can be found in the notion of "the center cannot hold." This image of entropy, a condition in which there is disintegration, is representative of how those in the position of power has contributed to the breaking down of any such moral order or ethical structure of guidance. Yeats alludes to the idea that it is the allure of power that causes such a condition. Consider his closing to the first stanza:
The best lack all conviction
While the worst are filled with passionate intensity.
This reveals a couple of elements. The first would be that those who are "filled with passionate intensity" willfully contributes to the moral or ethical decay of the setting. At the same time, Yeats suggests that those who are "the worst" are those in the position of power, suggesting that it is this power that causes individuals to abuse the constructs of power. It is this as representative of the allure of power where people have behaved in unethical ways.