Jane, great article.
Only this weak was I speaking to someone about "speaking truth to power".
I work as an advisor to Politicians and Executives.  Early on in my career it became clear that often persons in these positions are simply looking for someone to ‘rubber stamp’ their positions, even unethical and illegal ones!   I made a conscious decision that I could not do that and so decided I would never be a full-time employee but would be a consultant advisor.  That way if the client wants to fire me – fine but I will continue to speak ‘truth to power’.
I believe if you are called to be a leader, or work with leaders, that this is a pre-requisite, as the stakes are high, especially in the political arena when the lives of the most vulnerable are impacted.
I love the fact that you shared practical questions to help one assess if we are 'ready' or ‘willing’ to speak up.  Not everyone is, and as you said there are different reasons but it’s an important consideration to bear in mind when we make career choices or take a promotion.  Money can’t be our sole goal or we could end up in a position that requires more than we are prepared to give.

Thank you!