In the case of Ford Motor Co. v. United States, 1971, the Supreme Court ruled against Ford Motor Company's claim that it was entitled to a tax refund from overpaid interest on loans taken out during World War II for defense production expansion. The court held that under Section 1481 of the Internal Revenue Code, companies were not allowed deductions for interest paid on indebtedness incurred or continued to purchase or carry obligations if the interest thereon is wholly exempt from taxation under this title. This meant that because Ford had borrowed money to buy government bonds whose interests were tax-exempted and then claimed deduction for those interests in its income taxes, it violated section 1481 which disallows such practice as double-dipping (benefiting twice). Therefore, any previous refunds given by mistake should be returned back to IRS.

In the dissenting opinion for Ford Motor Co. v. United States, the justice argued that Ford's actions did not constitute a violation of anti-trust laws as they were merely an attempt to maintain their competitive position in the market. The justice believed that there was no evidence showing any intent by Ford to monopolize or restrain trade and competition within the automobile industry. They also pointed out that many other companies had similar practices without facing legal consequences, suggesting inconsistency in enforcement of these laws. Furthermore, they contended that penalizing such behavior could discourage healthy competition and innovation among businesses which would ultimately harm consumers' interests more than it protects them.