Linda J. Romano-Murphy challenged a trust-fund-recovery penalty under 26 U.S.C. § 6672 after the IRS assessed it without deciding her timely pre-assessment protest. The Tax Court sustained the assessment and denied her motion to vacate without deciding whether the IRS had to make a pre-assessment administrative determination. The Eleventh Circuit held that a taxpayer who timely protests a proposed § 6672 penalty is entitled to that determination under the governing statute and regulations. Although the IRS later considered her liability at a collection-due-process hearing, the Tax Court had not found whether the procedural error caused prejudice or was harmless. The court vacated the Tax Court’s judgment and remanded for it to decide whether the error was harmless or required setting aside the 2007 assessment or another corrective action.