In the case of Atlantic Refining Co. v. Federal Trade Commission, 1964, the Supreme Court ruled in favor of the Federal Trade Commission (FTC). The dispute arose when Atlantic Refining Company was accused by FTC of violating Section 2(a) and Section 5 of the Clayton Act for discriminatory pricing practices between different purchasers that could potentially harm competition. The company argued that it had acted within its rights under a cost justification defense as provided by law, stating their price differences were due to varying costs in serving different customers. However, upon review, the court found insufficient evidence supporting this claim and held that Atlantic failed to meet its burden of proof for cost justification defense against price discrimination charges. Therefore, they upheld FTC's cease-and-desist order against Atlantic’s discriminatory pricing practices.

In the dissenting opinion for Atlantic Refining Co. v. Federal Trade Commission, Justice Harlan argued that the majority's decision to uphold FTC orders against vertical integration in the petroleum industry was based on a misinterpretation of legislative intent and an overextension of administrative authority. He contended that Congress did not intend for Section 5 of the Federal Trade Commission Act to be used as a tool to reshape entire industries or prohibit business practices merely because they were deemed undesirable by regulatory agencies. Instead, he believed it should only be applied when there is clear evidence of anti-competitive behavior causing harm to consumers or competition itself - which he found lacking in this case. Furthermore, Justice Harlan criticized the majority's failure to provide sufficient guidance on what constitutes "unfair methods of competition," leading potentially towards arbitrary enforcement and uncertainty within businesses about their legal obligations under federal law.