Want a divorce from the United States of America? It'll cost you $2,350

Renouncing your citizenship is subject to the approval of the Secretary of State, believe it or not. And you have to take an oath:

I desire and hereby make a formal renunciation of my U.S. nationality, as provided by section 349(a)(5) of the Immigration and Nationality Act of 1952, as amended, and pursuant thereto, I hereby absolutely and entirely renounce my United States nationality together with all rights and privileges and all duties and allegiance and fidelity thereunto pertaining. I make this renunciation intentionally, voluntarily, and of my own free will, free of any duress or undue influence.

Here is the form: https://eforms.state.gov/Forms/ds4080.pdf