This paper explores Internal Revenue Code (IRC) section 6404(e)(1). Enacted in 1986 and amended in 1996, this section authorizes the Internal Revenue Service (IRS) to abate assessed interest on tax deficiencies and underpayments to the extent attributable to prescribed categories of procedural error or delay committed by the IRS in the course of audits and other routine processes. A companion provision, section 6404(h), enacted in 1996, grants the Tax Court jurisdiction to review IRS abatement determinations for abuse of discretion. This paper analyzes the statutory language, legislative history, Treasury regulations, and other administrative materials, as well as post-1996 Tax Court opinions, toward identifying problematic factors that to date have frustrated the stated congressional intent. Recommendations for clarifying statutory amendments are noted.