The phrase "moral backbone" refers to having strong principles and values that guide one's actions and decisions in a good and ethical way. Full definition
In your ignorance and lack of moral backbone you will destroy a cornerstone of our democratic freedom. (canadianlawyermag.com)
I'm very impressed with this manifesto, it's always good to know that a business is being operated with a strong moral backbone to guide its future. (phoenixrealestateguy.com)
It is not because they have some sense of moral backbone. (politics.co.uk)