The foundations of the separation of powers principle and those of antitrust present an actual and renewed interest, as we are currently witnessing a resurgence of non-economic concerns in the antitrust literature. This observation especially relates to the United States, but many issues raised in this country are also relevant in other jurisdictions. Several key provisions of antitrust national laws or European treaties are rather vague, leaving broad room for interpretation, and have remained unchanged in substance for decades, which may open a connection between the political content of antitrust viewed historically and prospectively; to a certain extent, the ball is now in the court of agencies and courts. The concentration of power in the digital era constitutes the starting point of the analysis, which continues with the observation that some digital platforms have significant political power and ends with the idea that such platforms have become important or even fundamental parts of the digital infrastructure of democracy.

Private regulation by dominant firms and the digital infrastructure of democracy controlled by some firms constitute the areas where the separation of powers principle, envisaged in a broad sense, and antitrust may share much common ground. A single dominant digital firm may adopt private regulation affecting an entire industry and even society at large, be an important part of the digital infrastructure of democracy and, through many means including lobbying, exercise a significant influence on public decision-makers. Such a firm concentrates an immense amount of politico-economic powers. At the same time, it is subject to antitrust laws and relevant from a contemporary and prospective separation of powers’ viewpoint. Antitrust could, in the end, contribute to the separation of powers in the digital era and, ultimately, to trust. Antitrust for trust, or the ultimate apparent antitrust paradox.

Separation of powers or, more exactly, the rule of law, due process or, in Europe, the right to a fair trial influence the institutional setting of antitrust or regulatory authorities and law enforcement. An increased role given to specific regulation or antitrust in order to tackle some fundamental issues posed by the concentration of economic-political power does not go without independent and impartial decision-making from an institutional and procedural, a personal or a financial and lobbying perspective.

The content of separation of powers is neither defined in constitutions, which usually do not explicitly guarantee this principle, nor in other legal texts. Its content cannot be circumscribed with precision. Several influential authors have dealt extensively with separation of powers. However, few of them were constitutional and economic thinkers. After careful analysis, but without claiming to be exhaustive, two major names stand out. The connection between reflections by Montesquieu and Hayek on the concentration of state power on one hand, and on economic concentration on the other hand, is illuminating and fascinating, but has never before been established. Aron also deserves a special mention in this regard, as he notably dealt with democracy and totalitarianism as well as competition in the same breath throughout some major parts of his work.

The contribution of antitrust de lege lata to the separation of powers is rather limited. A role should nevertheless be granted to specific legislation, regulation or practices and, possibly, antitrust de lege ferenda, especially with respect to the control of the digital infrastructure of democracy, the prohibition of distortions of the electoral and democratic process, the conclusion of certain governmental contracts with large or, a fortiori, dominant platforms, as well as the regulation and deconcentration or decentralization of artificial intelligence and the Metaverse. Artificial intelligence and, notably, machine learning based on data face a cycle of concentration accentuating the need for regulation. Deconcentration or decentralization may be envisaged, imposed or incentivized. Furthermore, limits are especially necessary when substantial autonomous powers are granted to forms of artificial intelligence. The Metaverse, for its part, may reshape society, politics, and economy around the globe in the future. From an antitrust perspective, the Metaverse poses at least two main issues: antitrust on the Metaverse and antitrust in the Metaverse.

The separation of powers principle and antitrust both relate to power – a multidimensional, multifactorial, contextual, and evolutive notion – and notably deal with the concentration or the abuse of power. The separation of powers principle primarily relates to the branches of government and state functions. For its part, antitrust is linked to economic power.

Antitrust may contribute to reduce the politico-economic power of certain dominant firms in the digital era. The perspective must however be broadened beyond antitrust, at least de lege lata, as the time may have come to elaborate upon a new scheme of separation of powers. Separation of powers is generally approached from a state-centered perspective, but a power-centered perspective more easily allows for a multidimensional approach to this principle.

Firms are not organized in a monolithic way; their organizations include checks and balances imposed by various sources. Separation of powers may be used, by analogy, in antitrust matters, especially to define organizational remedies or commitments. The search for an analogy between separation of powers and antitrust starts intuitively with the power of an agency or court to break up or unbundle a firm and naturally follows with merger control. A more promising avenue for analogy, though, resides in the fact that firms sometimes possess, de facto, regulatory powers in an industry, raising concerns inter alia on their organization. The reflection on organizational remedies or commitments is premised on the need for additional checks and balances within or on dominant firms whose platforms have a significant impact on society or democracy. It may ultimately lead to the creation of platform assemblies or parliaments. Finally, antitrust may also be raised as an argument or a defense to avoid or reduce sanctions and to get a merger approved.

The separation of powers principle and antitrust both relate to power and, notably, deal with the concentration of power. However, they are usually conceptualized, analyzed, and promoted separately. Separation of powers primarily refers to branches of government or to the main functions of the state and, in this respect, to public or state power or powers, while the economic power of private or, to a lesser extent, public firms is at the core of antitrust. Though appealing, this distinction is not clear-cut. These powers interact with one another. The concentration of politico-economic power in one or a few hands also raises fundamental issues in a democracy. Currently, and in the future, special attention must be given to the fact that a few digital platforms contribute to the digital infrastructure of democracy.

The digital economy raises important concerns relating to the concentration of economic-political power and, consequently, to the separation of powers in a broad sense, or more narrowly to checks and balances. Several recent or proposed pieces of legislation, especially in Australia, the European Union, Germany, India, Japan, South Korea, the United Kingdom, and the United States aim at tackling some issues posed by large digital platforms. These recent or proposed pieces of legislation all address important issues in the digital economy, and some of them could contribute to reduce entrenched market concentration, however, to a degree that remains to be defined. The most comprehensive set of bills from this perspective was introduced in the U.S. Congress during the last two years. However, even in this country, the concentration of politico-economic power in a few firms and the control of the digital infrastructure of democracy by them would remain widely unregulated, as in other countries, should Congress pass the proposed bills.