Here's the part most people miss: the conversations you've had with your CPA about your IRS problem are discoverable. The IRS can summon your accountant, put them under oath, and ask exactly what you told them. There is a limited practitioner privilege under Section 7525, but it evaporates in the two places you need it most — criminal matters and anything the government decides to treat as one.
What Privilege Actually Covers
Attorney-client privilege protects communications made for the purpose of obtaining legal advice. Full stop. It survives criminal referral, it survives summons enforcement, and the IRS cannot make me testify about what you told me. That protection is the foundation everything else gets built on, because you cannot defend a case you're afraid to talk about honestly.
When your case needs accounting work — and most do — the answer is a Kovel arrangement: I retain the accountant, and their work runs through the privilege instead of around it. Done correctly, the analysis stays protected. Done backwards, with the client hiring the accountant first, the privilege never attaches.
Why This Matters Before You Think It Does
Most people call a tax attorney after the situation turns serious. The smarter ones call before. Once you've explained the whole story to a preparer over the years, those conversations exist in the record forever. Privilege isn't retroactive.
If there are facts in your case you wouldn't volunteer to a Revenue Agent — unreported income, amended stories, anything from the gray zone — those facts should only ever be discussed with someone who cannot be compelled to repeat them. That's not paranoia. That's how the system is built, and the IRS knows it better than you do.