Attorneys, CPAs, and enrolled agents can all represent taxpayers before the IRS - the power of attorney form treats them identically. So the choice is not about who is allowed in the room. It is about three structural differences and one practical one.
Privilege Is the Big Structural Difference
What you tell an attorney is protected by attorney-client privilege - in civil matters, in criminal matters, in court. What you tell a CPA or enrolled agent has only a limited statutory protection that evaporates in criminal cases and many other contexts; the government can summon your accountant and compel testimony about everything you said. For routine compliance this rarely matters. For unfiled years, unreported income, offshore accounts, or anything you would hesitate to put in writing, it is the whole ballgame - which is why sensitive cases start with an attorney, who can then engage the accountant under privilege when number-crunching is needed.
Litigation Is the Second
Only attorneys litigate. If your case could end in Tax Court - and every Notice of Deficiency points there - representation that can actually file the petition and try the case carries negotiating weight that representation that cannot, does not. The IRS evaluates settlement through hazards of litigation, and hazards are more credible coming from someone who litigates. Enrolled agents and CPAs hand the case off at the courthouse door; that handoff has a cost in continuity and in leverage.
What Each Does All Day
The practical difference: CPAs are accounting professionals - returns, books, financial statements - and the best ones are worth their weight in gold for exactly that. Enrolled agents are IRS-credentialed practitioners who often focus on representation and do it well at the routine tiers. Tax attorneys live in controversy: collections defense, settlements, audits, appeals, litigation. For a complex return, hire the CPA. For a payment plan on a modest balance, an EA may be the economical choice. For a dispute with stakes - discretionary decisions, sensitive facts, hard deadlines - the controversy lawyer is the matching tool.
Teams beat solo acts in big cases anyway: I work alongside clients' CPAs constantly, each doing the part we do all day. The free consultation sorts out which configuration your situation needs.