First of all, your bylaws are your bylaws and must be adopted by your group. The principal can't just write a new set and say "here's how your group is going to run." It's also a very bad idea for principals to try to micromanage in that way. The result, as you're finding out, is resentment and a plummeting rate of parent involvement.
It's important in these situations to find out what lies behind the attempt to micromanage your group. Approach the principal in a businesslike and non-emotional way to discuss the direction of your group. Listen to what the principal has to say, and discuss ways to adjust that will make the principal feel more comfortable. But also point out to him that his actions are likely to significantly harm involvement, make fundraisers less successful, and overall diminish the impact parents are able to make on the school.
If your principal is reasonable and you do this in a businesslike way aimed at finding a solution, I think you'll be able to reach a compromise. In the meantime, however, you should absolutely get your own EIN (form SS-4 from the IRS, irs.gov). It takes about 15 minutes; you can do it online. Open your own bank account, and begin the process toward achieving 501c3 tax-exempt status and independence.
The article 501c3 for PTOs explains the process.
Good luck, and please let us know how things go!
- Craig
Links in this post:
501c3 for PTOs: https:/classic.ptotoday.com//pto-today-articles/article/394-501c3-for-ptos