At my pay-grade

Two questions:
1. Is there evil?
2. Can we defeat evil?

First, the definitions:
Evil:
def 1. intentional cruel, injust and/or selfish acts
def 2. acts contrary to the teachings of a specific religion

Defeat:
def 1. Win a victory over; beat
def 2. Thwart; prevent the success of.

So, this answer actually has 4 parts.
Q1. Can we thwart cruel, unjust and/or selfish acts?
A1. Yes. All it takes is some bravery and courage. It is done all the time by average people, soldiers, police and firefighters, and others.

Q2. Can we win a permanent victory over all intentional cruel, injust and/or selfish acts?
A2. Since bad behavior is part of human nature, this may be more difficult. To do top down is to remove free will and thus to eliminate morality, which is the choice of doing good over evil. Even if we could do this top down, it is unlikely to lead to a better world. The main problem is that it leads to defining inequity as evil, with the haves being evil and the have-nots being victims, which is not always true and is frequently wrong. Bottom up, as people choose to live better lives, the world will truly become a better place.

Q3. Can we thwart acts contrary to the teachings of a specific religion?
A3. Only with extreme top-down Taliban/SS/"politicially correct" type of policies.

Q4. Can we win a permanent victory over those who would act contrary to the teachings of a specific religion?
A4. This actually falls into the provice of religion, as only G-d can stop all those who would act contrary to a specific religion. However, as above, mind-altering medications, indoctrinations, and "thinning of the herd" can go a long way to make this a reality.

So, when you hear arguments about defeating evil, remember that evil exists in all of us at one time or another. All we can do is thwart people committing evil acts as they happen and try to live as good lives as we each can do if we really try.