“Litigants flout court rules at their peril. District courts have broad discretion to punish them by striking their briefs if needed. We will not upset these sanctions lightly.” When an appellate court’s opinion begins like this, it’s obvious the litigator should have hired Sullivan | Simon to assist. Here, Brace’s attorney repeatedly violated the court rules. So, the District Court struck Brace‚Äôs brief in response to a summary judgment motion, treated the Government’s motion as unopposed, and granted the motion. The Third Circuit affirmed, finding the severe sanction was not an abuse of discretion.