Ronald Byers appeals from an adverse decision of the Tax Court, 1 challenging that, court’s determination of his tax-deduction amount for tax year 2003, its refusal to enforce a document subpoena, and its imposition of sanctions.

After careful review, we conclude that the Tax Court (1) did not clearly err in *623 calculating the tax-deduction amount at issue, see Blodgett v. Commissioner, 394 F.3d 1030, 1034-35 (8th Cir. 2005) (standard of review); (2) did not abuse its discretion in declining to enforce Byers’s subpoena, see United States v. Roach, 164 F.3d 403, 412 (8th Cir. 1998) (same), cert. denied, 528 U.S. 845, 120 S.Ct. 117, 312, 145 L.Ed.2d 99 (1999); and (3) did not abuse its discretion in imposing a sanction under these circumstances, see 26 U.S.C. § 6673(a)(1) (stating that the tax court may impose a penalty when the taxpayer maintains proceedings primarily for delay or takes a frivolous or groundless position). Accordingly, we affirm.