I made a start at addressing this question here. In that post, I pointed out that evil, in the sense of deprivation, can make one apparently strong through insensitivity. A long-time smoker has damaged lungs, but even though his lungs are weaker than healthy lungs, through that very weakness they can better endure a smoky environment. An evil man will become insensitive to the nature of his deeds, and so find them easier to perform. In that sense he is more "powerful."
The Western philosophical tradition, starting with Socrates, taught that such "power" is not really power at all. The argument is teleological. Every being is created with an end (or hierarchy of ends) that is an expression of its nature (or, if you don't like creation, every being simply has an end that is an expression of its nature.) Power is a measure of the extent to which a being can fulfill its end through itself. Beings that are entirely dependent on other beings to fulfill their ends are not powerful; beings that are entirely independent of other beings to fulfill their ends are supremely powerful (e.g. God). The end of a tree is to grow tall, become a home for birds and other animals, become wood for man, and make more trees. But the tree is dependent on the wind to spread its seed, the nature of the soil in which it grows, the degree of competition from other trees, and the amount of sunlight in its environment. If the soil is bad or larger trees shade it from the sun, the tree cannot pick itself up and move to another location. To that extent it is not powerful. An animal, on the other hand, if the conditions are not right, has the power to move itself to a better location. It can also actively seek out and hunt its food, where the tree can only passively absorb it.
Man is the supremely powerful terrestrial creature because he not only has an end, but he has the power to know that end and consider various means to achieve it. The dog needs food and can move himself to find it, but he cannot analyze how different foods effect him, let alone ask himself why he eats food in the first place. Man is more powerful than the dog because he is not limited to acquiring food through instinct; he can understand what food is and why he needs it, and can consider other ways of getting food. He can also consider food in the light of the hierarchy of ends that constitute his own nature. He may deprive himself of food (e.g. in fasting) for a higher end.
Man can know his own end. He is ultimately free to accept or reject that end. But even if he rejects it, his end is still his end; his relationship to his end will be one of despair (the sickness unto death.) When man acts with moral evil, he is acting in a way that cannot be conducive to his end; for Socrates, this means he acts without power, for power is the capability to fulfill an end. In thwarting his own end, therefore, man only acts with apparent power.
Since evil does not act according to a being's end, it is necessarily destructive.
"It came to me suddenly that evil was, perhaps, necessarily always more impressive than good. It had to make a show! It had to startle and challenge! It was instability attacking stability." (Agatha Christie, The Pale Horse).
But evil can destroy only to the extent that it is, and is therefore good. It is only to the extent that evil is stable that it can cause instability. Socrates uses the example of the criminal gang that, while unjust to others, must be just within its own ranks to be effective. It is only because the gang fulfills its true end to some extent that it has power at all.
The government has used this principle to destroy the Mafia. Fifty years ago, the code of omerta was strong and mobsters lived according to a strict code that made them powerful. The Mafia was largely destroyed, in the 1980's and 1990's, when the government was able to get mobsters to turn on each other. The FBI destroyed the stability of the mafia by turning its instability inward rather than outward.
The difference between the modern and the classical view of power is that modern power is simply "the ability to make things happen," whatever their nature. The classical view is more restrictive. Power is not merely the ability to make anything at all happen, but only things that are conducive to a being's own end. True power is essentially creative rather than destructive. The classical view has this going for it: The difference between the good man and the evil man is not one of raw capability; it is that the good man orders his actions to his own true end while the evil man does not. The good man rationally refrains from certain actions that the evil man is willing to perform. But the good man has the raw capability to perform the same actions as the evil man; he can "make those things happen" in the modern sense, but he refuses to because they are not ordered to his true end. So the evil man is powerful, yes, but it is not in his evil that he is powerful.