They work hand in hand. Every politician needs a supporter, preferably one that is wealthy.
Just take a drive in the DC Metro region...enormous wealth beyond most peoples imagination, and they vote overwhelmingly for Democrats. So what do you infer?
The federal reserve controls the monetary policy. It is not part of the goverment and it is not private. It is a cartel much like OPEC is for oil except that it is solely responsible for the dollar.
The govt controls taxes, and levies such as tariffs...
Having said all that...There is tremendeous influence on both by too few people...