Remember who put him there, if it was bad choice, it means upper management made a bad decision. In my experience upper management will do anything but admit to a bad decision.
Just silently leave for another job, try to make sure you will get a good/neutral reference. Remember future employers will just think your bad/unskilled if you get a bad reference rather than the fact you got into politics. Larger companies have an automatic no, to bad references and won't accept excuses. Since they assume your a bad person/almost criminal (the only point large corporates will give a bad reference normally) and probably lying. Limiting you to small companies for your next job.
Its nice to think you can be a hero and fix this, but you can only do that if your someone with significant power in the company like a founder, or an early employee who is best buds with senior management. Since HN is full of these types, they can be idealistic.
I've been through situations like this, and this is what I would do now rather then potentially making your life hell.
Situations like this is a massive problem with modern company structure.