Believe it or not, in most states you do indeed have the right to self-defense against the police.[0] If the police are acting with excessive force, likely to cause great physical harm, you are within your rights to choose to fight back (notwithstanding the fact that this will probably get you killed). This principle was a big part of Randy Weaver’s successful defense after the Ruby Ridge stand-off.

[0]: https://www.nolo.com/legal-encyclopedia/resisting-arrest-whe...