Should antitrust law focus primarily on measurable performance outcomes such as price and output as indicated by Robert Bork’s Consumer Welfare Standard? Or is it more important to concentrate on whether conduct undermines the competitive process itself as per the newly revitalized Protect Competition Standard?
Antitrust law today stands at a crossroads. For decades, the dominant framework guiding courts and enforcement agencies has been the Consumer Welfare Standard (CWS), closely associated with the Chicago School and Judge Robert Bork. More recently, a revitalized Protect Competition Standard (PCS), advanced by scholars often associated with the “New Brandeis” movement, has gained prominence. The debate between these standards is frequently framed as a stark choice between incompatible visions of antitrust. In our recent article, we argue that this characterization is overstated. While the standards diverge in important ways, they share substantial common ground. Understanding both their overlap and their differences is essential for scholars, courts, policymakers, practitioners.
What Is an Antitrust Standard?
An antitrust “standard” is not a rule, but a general framework that determines what counts as legally relevant when evaluating challenged conduct. In open-textured areas—such as the rule of reason, monopolization, and merger analysis—standards help courts decide what to prioritize. Should judges focus primarily on measurable performance outcomes such as price and output? Or should they instead concentrate on whether conduct undermines the competitive process itself?
The CWS and PCS answer these questions differently.
Focus and Method: Performance Versus Process
Both standards value competition. Both consider price and output. However, they diverge in emphasis and method.
The PCS focuses on market structure and firm conduct—what industrial organization economists would call the “structure–conduct–performance” paradigm. The PCS emphasizes preserving rivalry and assumes, consistent with congressional judgment, that competitive markets will generally produce socially desirable outcomes. If conduct reduces rivalry by eliminating competitors, raising barriers to entry, or entrenching market power, the PCS views that as presumptively problematic—without requiring detailed proof of downstream price or output effects.
The CWS, by contrast, places performance metrics at the center of analysis. Under this approach, conduct is unlawful only if it reduces some measure of economic surplus—often operationalized as higher prices, reduced output, diminished innovation, or lower quality. Even when conduct restricts competition, defendants may prevail if they demonstrate offsetting efficiencies that increase consumer surplus.
Importantly, however, the standard selected does not determine the outcome. Strong or weak enforcement can occur using either framework. The difference lies less in results than in analytic orientation: the CWS is consequentialist and outcome-focused; the PCS defers to Congress’s judgment that protecting competition itself advances multiple social goals.
Divergent Origin Stories
The CWS is most closely associated with Robert Bork’s The Antitrust Paradox. Bork equated consumer welfare with economic surplus and argued that antitrust law should be drawn as a “mesh” that stops output-restricting behavior while allowing efficiency-enhancing conduct to pass through. Although there has been debate over whether Bork meant consumer surplus alone or total surplus, the modern CWS is widely understood as putting price and output effects at the center of the analysis.
The PCS, by contrast, is a reformulation of older antitrust traditions. It draws on the legislative history of the Sherman and Clayton Acts and on Supreme Court language emphasizing the preservation of competitive markets, alone, as the best means to achieve the (possibly sometimes conflicting!) goals Congress cared about: price and output effects, and political democracy, small business opportunity, and dispersion of economic power. Contemporary proponents—including scholars such as Lina Khan, Tim Wu, and others—have revived this process-oriented approach.
Practical Differences: Mergers and Monopolization
In many cases, the two standards converge. But differences emerge in close cases—especially regarding efficiencies and procompetitive justifications.
Merger policy provides a telling example. The 1982–2010 Merger Guidelines reflected a CWS orientation, focusing heavily on price effects and permitting efficiencies to rebut presumptive harms. By contrast, the 2023 Guidelines emphasize structural concerns, trends toward concentration, and broader competitive harms. Efficiencies are cognizable only if they restore competition itself, not merely if they promise lower prices.
In Sherman Act rule-of-reason cases, both standards use similar tools in the first stage of analysis, including evidence of market power and harm to competition. But they diverge at the justification stage. Under the CWS, defendants may defend restrictive conduct by showing consumer-surplus-enhancing efficiencies. Under the PCS, procompetitive justifications must themselves be competition-enhancing—such as solving free-rider or moral hazard problems. The menu of acceptable defenses is thus narrower.
Statutory Fidelity and Precedent
Our review of the statutory text and legislative history reveals little support for the claim that Congress intended consumer surplus maximization as the sole goal of antitrust. The Sherman Act’s Section 1 prohibits “restraints of trade,” a term rooted in common-law doctrines concerned with limiting rivalry. And at the time of the passage of the Sherman Act, the common law of monopolies applied to necessities of life, such as food, while Section 2’s prohibition on monopolization goes further. Finally, the Clayton Act prohibits mergers that may “substantially lessen competition”—not merely those that are inefficient, as claimed by Bork.
The legislative history of the Sherman, Clayton, and Robinson-Patman Acts repeatedly references concerns about concentrated economic and political power, protection of small businesses, and democratic governance. These goals align more naturally with the PCS than with a single-minded surplus objective.
Supreme Court precedent is more ambiguous. Since the late 1970s, the Court has often referenced “consumer welfare.” Yet its actual reasoning frequently centers on preserving competitive processes rather than calculating surplus. On balance, we conclude that the Court has not definitively endorsed either standard to the exclusion of the other.
Economic Theory and Welfare
Both standards rely heavily on positive economic theory—industrial organization models, market definition, and empirical evidence.
However, they diverge in their relationship to normative economics.
The CWS purports to ground antitrust in welfare economics. Yet twenty-first century welfare economics has largely moved beyond the Marshallian consumer-surplus framework that inspired Bork, and it has also moved beyond the mid-twentieth century improvements to that framework, namely compensating and equivalent variations and the Kaldor–Hicks criterion—actually, the Kaldor criterion and the Hicks criterion—because they introduce conceptual and distributional difficulties. The distributional difficulty is that surplus-based and compensating/equivalent-variation-based analyses implicitly give greater weight to the preferences of wealthier individuals and may systematically worsen inequality over time.
The PCS does not rest on welfare economics. Instead, it defers to Congress’s normative judgments about the social value of competitive markets.
Social Welfare and the Broader Goals of Antitrust
If the ultimate aim is human well-being, what does the evidence show?
Research on happiness suggests that increases in GDP per capita in wealthy countries—increases in “efficiency” as they are sometimes called—have limited impact on subjective well-being. By contrast, income inequality has strong and consistent negative effects on social trust, longevity, educational achievement, crime, mental health, and other measures of social well-being. Dispersing economic and political power tends to reduce income inequality and may also contribute to autonomy, community stability, and democratic resilience.
The CWS’s emphasis on output and surplus can indirectly mitigate inequality by constraining monopoly rents. But it does not treat inequality reduction as an objective. The PCS does not either: its only objective is preserving rivalry. However, the legislative history of the antitrust statutes shows that Congress saw protecting competition (preserving rivalry) as a means to disperse private power and protect opportunity. Inequality’s consequences and inequality reduction were not only Congressional concerns; they are also the concern of much of twenty-first century welfare economics.
Conclusion
The CWS and PCS share more common ground than is often acknowledged. Both depend on modern economic tools and both seek to preserve competitive markets. Yet they differ in emphasis: the CWS privileges performance metrics and surplus, while the PCS prioritizes rivalry and structural safeguards.
In our view, the PCS more faithfully reflects the text and history of the antitrust statutes and better aligns with contemporary economic scholarship on social welfare—particularly the central role of income inequality. At a minimum, policymakers and courts should recognize that the choice of standard is not merely technical. The choice of standard should defer to Congress’s judgment about how to achieve its purpose for antitrust law, which was to help bring about the kind of economy—and society—Congress sought to foster.
