Power does not only come from money, though (but is obviously a part of it). Having, say, $50m in the bank does not by default give you power. In most cases, you will still need to run in certain circles and be accepted by certain people.
Its a chicken and egg scenario. Money confers a certain level of power. Power, however, does open doors to opportunities to make money.
An example of money granting power would be Donald Trump. Do you really think Trump would be where he is politically if he wasnt wealthy?
An example of power opening doors to money is Barack Obama. He and Michelle were nowhere near wealthy 10 years ago. Now, after several book deals, speaking engagements, and much more, they are financially in a financial position that many Americans would consider to be wealthy - albeit nowhere near Donald Trump level.