Gales of Change: Gail Slater’s Exit Signals Selective Federal Antitrust Enforcement

By Robert H. Feinberg and Thomas Williams

On February 12, 2026, Assistant Attorney General Gail Slater resigned as head of the Department of Justice’s (DOJ) Antitrust Division. Her departure signals a new era of selective federal antitrust enforcement. As federal enforcement priorities shift, state attorneys general are stepping into the vacuum. For companies navigating antitrust risk, the enforcement landscape is fragmenting — and becoming far less predictable.

I. Selective Enforcement As the New Norm

One of Slater’s most notable enforcement actions — the June 2025 settlement in United States v. Hewlett Packard Enterprise Co. — is already unraveling. In January 2025, the DOJ brought suit under § 7 of the Clayton Act against Hewlett Packard Enterprise (HPE),¹ alleging that its $14 billion acquisition of Juniper Networks would substantially lessen competition in enterprise-grade wireless networking because two firms would control 70% of the market.² The day before trial was to begin, the parties reached a settlement agreement, requiring HPE to divest its “Instant On” business and license Juniper’s Mist AI Ops source code.³

However, after news outlets reported that HPE had hired two individuals close to the President to lobby on its behalf, the attorneys general of 12 states and the District of Columbia moved to intervene in the Tunney Act proceedings, which was granted by the district court.⁴ The attorneys general are now entitled to participate in the district court’s Tunney Act proceedings which will consider the “competitive impact of such judgment” and the “impact of such judgment upon competition in the relevant market”⁵ to protect the states’ own pro-competitive interests.⁶

In the entertainment space, the DOJ recently launched a formal investigation into the proposed acquisition of Warner Brothers citing potential breaches of § 7 of the Clayton Act and § 2 of the Sherman Act. Regulators are examining whether the deal would substantially lessen competition or result in monopolization. The timing of the investigation follows just days after a competing firm in the Warner Brothers bidding war cleared the statutory waiting period under the Hart-Scott-Rodino Antitrust Improvements Act.⁷

If Warner Brothers is acquired, the transaction would create a vertically integrated streaming giant with both substantial content production capabilities and a dominant distribution platform — raising significant questions about market concentration in the rapidly evolving video entertainment industry. As streaming services and similar apps have pivoted towards vertical, short-form video content, this business decision may prove dispositive in DOJ’s investigation. A critical consideration for any antitrust analysis of the Warner Brothers acquisition under the Sherman Act is the recent decision in FTC v. Meta, in which the district court held that the relevant market was all short-form video platforms that competed for users’ attention.⁸ Under this reasoning, the acquiring firm may not compete solely with other subscription video-on-demand services. Instead, the relevant market might encompass a broader universe of short-form video entertainment options — i.e., all other platforms and apps competing for consumers’ “marginal time.”⁹

If this broader market definition is applied to either proposed acquisition, the combined firm’s market share may appear substantially lower than it would under a narrower, streaming-only market. The extent to which the new Antitrust Division leadership embraces such reasoning in an antitrust investigation — and what it portends for enforcement — remains to be seen. Likewise, state attorneys general may bring their own antitrust enforcement actions.

The upcoming United States v. Live Nation trial will likely reveal if selective enforcement extends to litigation that is already in progress. The DOJ, along with 30 state attorneys general, filed a civil antitrust lawsuit against Live Nation Entertainment (Live Nation) and its wholly owned subsidiary Ticketmaster in 2024 during the Biden Administration.¹⁰ The lawsuit alleges that Live Nation–Ticketmaster unlawfully exercises its monopoly power in violation of §§ 1 and 2 of the Sherman Act in ways that harm competition and impose barriers to competition, limiting the entry and expansion of its rivals.¹¹ Trial is set for March 3, 2026. With Slater’s departure, the change in leadership at the Antitrust Division may affect how the DOJ approaches settlement negotiations or trial strategy in this closely watched case.

II. What Companies Should Know in the New Antitrust Landscape

Under the current Administration, a pattern of fragmentation is beginning to emerge: federal antitrust enforcement is becoming more selective, and firms cannot rely on DOJ decisions alone to assess their risk exposure in the M&A field. State attorneys general possess independent authority to enforce federal antitrust laws under § 16 of the Clayton Act,¹² and may bring parens patriae suits to enjoin mergers and other anticompetitive conduct that injure their citizens. Firms navigating this fragmented landscape should keep three principles in mind.

First, federal clearance does not end the inquiry. The HPE–Juniper settlement demonstrates that even a federal resolution may unravel when state enforcers view it as inadequate — particularly where lobbying or political influence taints or appears to influence the process. A deal approved by Washington may face litigation from Phoenix, Austin, or Sacramento. Proactive engagement with state regulators — before concerns harden into litigation postures — can mitigate this risk.

Second, market definition is malleable — and contestable. The investigation into high-profile acquisitions shows that the same transaction may succeed or fail depending on how regulators define the relevant market. A narrow streaming-market analysis yields a different result than the broader “attention economy” framework adopted in FTC v. Meta. Firms should develop robust economic analyses that can withstand scrutiny under wide and narrow market definitions.

Third, consider documenting procompetitive justifications from the outset. In an environment where the appearance of political influence can trigger state intervention — as it did in the HPE settlement — and where litigation initiated under one enforcement posture may conclude under another — as in Live Nation, with 30 state co-plaintiffs standing ready to press forward — firms should consider building contemporaneous records demonstrating consumer benefits, innovation effects, and efficiency gains that can withstand scrutiny from any enforcement agency.