"Cognitive Dissonance" is where our beliefs, behaviors, and attitudes are in conflict, and to avoid the discomfort, we use minimizing and coping tactics to deal with this "disharmony." For example, those who "text while driving," where many know it's dangerous, but proceed to do it anyway.
Following along the same lines:
If you held strong moral and political beliefs that aligned with a particular political candidate you supported, or one already in a position of power, and knew they had a long history of corruption or views that marginalized and hurt others, would you:
A) Continue to support that person, and either say nothing or defend them 100%.
B) Default to "they have evolved or will evolve, and they are not the same person," knowing they have not.
C) Continue to support them, but question and hold them accountable for their actions, hoping they will evolve.
D) You have had enough and start to speak out, making sure they are never elected (or re-elected), but risk alienating those who align with your moral and political beliefs.