Uzi, as a deaf, aged, and independent thinker, I have suffered the effects of harassment much as you - and others here - have. I agree with all your outrage and advice. I want to add my 2 cents worth. Never ever resign: make your employers fire you and make it hard for them to do that; have your recourses sourced and planned out. The senior residence Corp where I worked accepted Medicare and was required to keep an HR office, the Director of which was also the corp's Associate Director, as well as the Director of Assisted Living where I worked. These were the three hats she wore and the the three titles conferred by them. I never knew which hat she was wearing on any given day, and she never told. It was quite impossible to get fair and equal promotion of rights under such a system, just as it is impossible to get it in government beurocracies It is next to impossible to fire a civil service employee, even your loathsome coworker. A boatload of complaints will not get it done, but a consistent paper trail of them just might make a small difference in a hearing. Yes, document, document, document. You might want to keep a journal, and when you have something that amounts to evidence, make a record of it and write a factual, objective complaint citing the attached copy of your evidence and other recipients of your complaint letter. Make three copies: one for you, one for the EEOC & one for the file. Address the original to your HR person and sign and date your documents to be sent. You must write the EEOC a letter explaining succinctly the "attached" and attach your complaint letter to it. Faxes and emails will work here, too, I think. You may want to simply orally recite your complaint to your HRadvisor, but if you do this, you really should ask her if it is OK to record the interview. You should ask her/him what action you might expect from your complaint and by what time you might expect to see it. Then wait and see what happens. Act like your HR is your best friend and give the person fair benefit of the doubt, but don't let him/her blow you off. Your HR should, at the very least, make a copy of your complaint that he signs and dates recvd and returns to you. He SHOULD do this, without a suggestion from you. If he doesn't, you have at least some idea of where he is coming from. You COULD let it rest, and then ask for confirmation in your followup letter, or perhaps do the confirmation yourself by opening with "This is to confirm blah blah blah" and then closing with a mild request for a signed/dated copy of your complaint. This is YOUR access to resources for equality. You may have to consistently and vigorously assert your access, but it is your access. Be positive and constructive in your suggestions, if you have any to make (it's always good to have constructive suggestions, though). Your supervisor may believe he is protected by a government shield, but the minute you step inside his door, he is yours. So after you've spoken to him, ask him you might best follow up with him. He will know you are serious and maybe he will be willing to do some things to make life less confrontational at work. If he doesn't, keep cool and keep at it.
I know that you know the above scenario may not be applicable to your situation. The principles will apply, however. You must foresee the consequences of your actions, and make sure that every action moves toward and ensures that consequence. You don't just make a telephone call, you make it and confirm it with a written follow-up. You don't talk about an interview, you provide a transcript or tape copy of the interview. If your co-worker wants some of your duties, figure out which ones are OK with you for him to have and ask him/her if (s)he'd be willing to meet with you and your supervisor to work something out. Don't know if that sort of thing is possible, but it is not a bad strategy if you don't want to be remembered as a troublemaker. If your co-worker refuses such an invitation, note it in your meeting with the Supervisor. Make requests - they don't hurt as long as they remain requests - ask for what you really want. Dwell in your issue until you can make a plan, then make it and stick to it. It will give purpose to your suffering.
My mother was my greatest and wisest mentor. She said, "Get it in writing." HOWEVER, had she she received all the writing I just wrote above, she would throw up. Good Luck. (She had a weak stomach that failed to empty)