Whether the harmless-error rule applies when a district court expressly relied on clearly erroneous factual findings in its credibility determinations and ultimate conclusion

QUESTIONS PRESENTED This case tests the boundaries of the federal harmless-error rule. The substantive dispute arises out of the Hague Convention and turns on whether a newborn child’s unmarried parents both intended to make the Czech Republic the child’s permanent residence. Expressly relying on certain facts to decide which parent to believe—and calling those facts “highly persuasive”’—the district court concluded they shared such an intention. The Eleventh Circuit rejected those same putative facts as clearly erroneous findings. Instead of remanding the case, the appellate court invoked its “substantial evidence” version of the harmless-error rule and affirmed. It did so on the rationale that, without the factual errors the district court relied on, there was “substantial evidence supportling] the district court’s ultimate finding regarding shared intent.” In doing so, the court exacerbated multi-circuit splits over the harmless-error rule and the Hague Convention. The questions presented are: 1. Does the harmless-error rule apply to clearly erroneous findings of fact if a district court expressly based its credibility determinations (and its ultimate conclusion) on those errors? 2. Ifa fact-finder relies on errors of fact for its conclusion does the presence of other substantial evidence to support that conclusion make the errors legally harmless? 3. Given the requirement of “habitual residence,” how does the Hague Convention apply to newborn children?