I think it can be done, but it does bring up multiple questions. Say there is magic that can be used by either side (good and bad), but it does not change when used by either side, there is no way to tell them apart. It seems pretty simple, but there are some holes.
How can good defeat evil if it is the same strength as the evil, of the same power and using the same tools?
Who's to say that this isn't implying that one can be of both good and evil?
Of course, I also agree with Leandra, the power in itself isn't evil. We can say we have magic in our world (Not real magic.

), the magic of the Bible, so let's use that as an example.
The Bible is/can be used for both good and evil. If used by say...an evolutionist, it will be changed. One cannot disprove the Bible without changing the context inside it. So, if evil uses the "magic" the "magic" will change according to evil's intent. What was once good will be used for bad and therefore shall be bad. And there shall also be holes and weaknesses.
The Bible can and is supposed to be and shall be used for good. If say, a Christian uses the Bible to disprove the evolution theory then the Bible shall not be changed. One does not need to change the context of the Bible to prove that which is already written clearly inside the first chapter. The "magic" stays in its purest form, as the day it was made. Therefore the "magic" is stronger and without holes. This makes the good stronger.
So, to conclude my ramble. Yes, magic can be neutral, but it should be affected by which side uses it. Nothing can be used by both good and evil and be neither good nor evil.
Bethany Faith