Respectful word that means "desiring power"

What is a good word to use for describing someone as "desiring power"?

I suppose power-hungry would work. Megalomaniac seems a bit much, but I can see how that works. I was wondering if there was another word, something I didn't know.

I'm using the word to describe a group of people, and I wish to be both descriptive and respectful.

aspirant

noun:

a person who has ambitions to achieve something: an aspirant to the throne.

(via Apple dictionary, which I think links to the OED)

Ambitious is a general descriptor that can be applied to power as well as other advantages that lead to success:

adjective

1 Having or showing a strong desire and determination to succeed:
a ruthlessly ambitious woman
_ODO

Since power is a key to success in most endeavors, people with a strong desire to succeed are often perceived as power-hungry, even if the pursuit of power is not their ultimate goal. Other people define success in terms of accumulating power, and these ambitious people are truly hungry for power. When describing projects, ambitious is more likely to have a positive connotation, but when applied to people, it can often harbor the negative connotations of the insatiable desire for power and wealth, as seen in The Huguenots, by Samuel Smiles:

He [Louis XIV] was proud, ambitious, fond of power, and believed himself to be the greatest of men.