In the United States v. O'Brien case of 1910, the Supreme Court ruled on a matter involving customs duties and importation laws. The defendant, O'Brien, was accused of fraudulently undervaluing imported merchandise to avoid paying full customs duties. He argued that he had relied on foreign invoices for valuation and thus did not intentionally commit fraud. However, the court found him guilty as charged because it held that ignorance or mistake about value does not excuse fraudulent underestimation of goods' worth when determining custom duties payable upon their importation into the U.S.. The court emphasized that an importer is required by law to exercise reasonable care in valuing imports for duty purposes and cannot simply rely on foreign invoices without further investigation if there are reasons to suspect they might be incorrect.

In the dissenting opinion for United States v. O'Brien, it was argued that the majority's decision to uphold a tax on foreign-built yachts violated principles of international law and comity. The dissent contended that such taxation could potentially lead to retaliatory measures from other nations, thereby damaging U.S. interests abroad. Furthermore, they believed this tax unfairly penalized American citizens who chose to purchase yachts built overseas due to their superior quality or lower cost compared with domestic options. They also questioned whether Congress had overstepped its constitutional authority by imposing a discriminatory tax aimed at protecting domestic industries rather than raising revenue - which is the primary purpose of taxation under the Constitution.