The United States brought this action against Alice, Cheryl, and Harvey A. Lan-grehr (the Langrehrs) and others to re *588 duce federal tax assessments to judgment and to foreclose on certain real property. The district court 1 entered a default judgment against the Langrehrs after they failed to respond to written discovery despite the court’s order to do so. The Langrehrs appeal, arguing the district court lacked jurisdiction and failed to protect their Fifth Amendment rights.

The district court had jurisdiction because the Langrehrs conceded they were domiciled in Nebraska and the federal income tax applies to residents as well as citizens. See 26 C.F.R. § 1.1 — 1(a); United States v. Jagim, 978 F.2d 1032, 1036 (8th Cir. 1992), cert, denied, 508 U.S. 952, 113 S.Ct. 2447, 124 L.Ed.2d 664 (1993). The Langrehrs did not raise a substantial threat of self-incrimination in the objections to written discovery that the district court concluded were frivolous and in violation of its prior discovery order. Upon careful review of the record, we find no abuse of discretion in the entry of default judgment. See Fed.R.Civ.P. 37(b)(2)(C); Anderson v. Home Ins. Co., 724 F.2d 82, 84 (8th Cir. 1983).

Accordingly, we affirm. We deny the government’s motion for sanctions.