To begin, I'd like to clarify a couple of things. While I do quite often use the word Wiccan to describe myself, and I do believe and follow the Rede of "Harm None" this term is not always entirely accurate in my case. The term Wiccan allows me to encompass many of my interests under that catch all word and makes filling out hospital, doctor's office or insurance forms easier but at the core level I am a Witch. I do spellwork and work with the Dark Mother as well as her Light Aspects, but it is done sparingly and with a great deal of thought and consideration for all potential outcomes.
I make very sure that I am prepared to accept the full consequences of those actions because there IS a karmic ripple and return to every action and deed. We've all heard that every action has an equal and opposite reaction. This is a simple law of physics, nature and the universe that cannot be avoided and it holds very true in magickal workings.
The difference between being Wiccan and a Witch is that a Wiccan believes everything can be changed or made better by surrounding it with love, white light and positive energy. While in many cases, positive change can take place, this is not always true. A Witch understands that the basic nature of a thing will remain true to itself. You cannot make a tiger change its stripes.
Let's not kid ourselves, there are evil people in the world. These people--the child abusers and molesters, the rapists, wife beaters and murderers, those who prey on the innocent and unsuspecting--they do not change and all the white light in the world is not going to change them. Sometimes it IS appropriate to hasten karma if someone is truly a threat to another.
The ideas and concepts of karma are well and good, but sometimes you must also have the courage to be an instrument of karma if it is truly justified. Just as there are police officers and prisons in the physical world, I believe that we also need some of this in the spiritual world. Another Witch I know of coined the phrase "Karmic Facilitator," where a Witch will in effect focus their energy towards someone holding them up to the Crone or Dark aspect of the Goddess for her karmic justice. She will know if the person is truly guilty and if karmic or spiritual justice needs to be hastened.
There is a very subtle yet key point in what I just said. I did not say that *I* set forces in motion *against* that person by wishing them ill. What I said is that I focus energy through ritual or spellwork that brings that person to the attention of the Goddess and let *Her* decide if karmic retribution is appropriate by *asking* that true justice be granted.
All and all, a Witch must always use common sense, ethics, morality and humanity in their workings. Just as you would hopefully not stand idly by and watch or turn away from a mugging, murder or rape in the physical world, you should not do the same in the Magickal realms. Your conscience must guide you in the spiritual and magickal worlds as well. Being a Witch brings with it great responsibilities and you must always reflect fore sight, humanity and compassion in your workings but at the same time use discretion and care to ensure that you are not becoming an abuser of your divine gifts.
I also speak about the ethics of ritual and spellwork in my rambling's entitled Love Magick and I Want Spells.
If by chance you are a Fundamentalist Christian and have the urge to heap fire and brimstone upon me for my thoughts here, please feel free, I have broad shoulders. Consider this first however. In essence you do the same thing on a regular basis. The only difference is you you call it prayer.