Walker Process: A Modern Assessment of an Antitrust Classic

• Pages: 29-38
• Date: 01 July 2025
• Published date: 01 July 2025
• Author: M. Sean Royall,Ross E. Elfand

SUMMER 2025 · 29

M. Sean Royall is a partner in the Washington, DC and Dallas, Texas

offices of King & Spalding LLP, where he serves as the firm’s Global

Practice Head for Antitrust & Consumer Protection. Ross E. Elfand is

a partner in King & Spalding’s New York office. The authors are deeply

grateful to Connor Brewer and Hope Garrison for their excellent research

support.

Walker Process:

A Modern Assessment

of an Antitrust Classic

BY M. SEAN ROYALL AND ROSS E. ELFAND

1965 HAS BEEN CALLED “THE MOST REVOLU

tionary year in music.”1 It was in that year, now six decades

ago, when the world first heard The Who’s “My Generation”

and the Rolling Stones’ “Satisfaction.” This was the year The

Beatles invented the stadium rock concert, and the year Bob

Dylan first went electric. Many songs from that era continue

to be played and enjoyed. Generations of listeners not even

born when they were released know their words by heart. We

call them classics because they have stood the test of time.

1960s-era antitrust decisions are a somewhat different

story. Most antitrust lawyers today would need to con-

sult the Internet or a treatise to be reminded of what the

Supreme Court’s Parke, Davis decision concerned—sub-

sequent changes in the law have made it an anachronism,

and other antitrust decisions from that period have simi-

larly fallen out of circulation.2 But not so with the Court’s

Walker Process decision.3 It is as relevant today as it was when

the decision issued in December 1965. By any definition, it

qualifies as an enduring antitrust classic.

In Walker Process, the Supreme Court first recognized

what the Court at the time deemed a “novelty”—a new anti-

trust cause of action.4 It held that enforcement of a patent

procured by fraud on the Patent Office can violate Section

2 of the Sherman Act where the requisite knowledge and

intent exist and the other elements of actual or attempted

monopolization are satisfied.5 In a concise but thoughtful

decision, the Court grappled with the concept that pat-

ent-based monopolies may in some respects be exempt from

antitrust enforcement, drew important distinctions between

per se and rule of reason analysis, reinforced the primacy of

market-based proof of effects on competition, and empha-

sized the concept of “exclusionary power” as a bedrock

Section 2 principle.6 The Court’s framing of the key issues

and elements of proof is still controlling law and virtually

every word of the decision has some continuing salience, as

the authors of this article can attest, having recently tried a

Walker Process case to a jury verdict and in the process navi-

gated a battery of pre- and intra-trial legal disputes.

That said, Walker Process arose through an appeal of a

motion to dismiss ruling, which necessarily limited the scope

of the Court’s analysis. Over the intervening decades, appel-

late courts, particularly the Federal Circuit, have added to

Walker Process jurisprudence, but some meaningful ambigu-

ities remain. We have in mind three areas of Walker Process law

that would benefit from further attention and development.

First, while courts have given in-depth attention to the

overlap between Walker Process claims and related patent law

defenses, including the particulars of what must be shown in

both contexts to prove fraudulent patent procurement, less

attention has been given to the specifics of what beyond pat-

ent fraud antitrust plaintiffs must prove. In particular, there

is a surprising degree of uncertainty surrounding precisely

what conduct-related proof is required to establish Walker

Process liability. As explained below, the Supreme Court in

Walker Process declined to embrace a per se liability standard

for fraudulent patent procurement claims. However, some

courts have allowed antitrust plaintiffs to rest their claims on

something more truncated than full rule-of-reason proof. In

fact, one commentator has referred to Walker Process claims

as falling into a category of “nearly per se illegal” conduct.7

This may be true in practice, if only due to the habit of some

courts to mistakenly overlook the distinct Section 2 proof

requirements that Walker Process claimants are required to

satisfy over and above proof of underlying patent fraud.

Yet, as explained below, that more streamlined (and in the

authors’ view, errant) truncated approach appears to be

directly at odds with what the Supreme Court intended.

Second, there is one area of Walker Process law in particular

where courts tend to become mired in confusion over applica-

ble proof standards: cases where the threatened harm to com-

petition is linked to the prospect of a future court- imposed

patent injunction. This scenario is not at all uncommon.

Walker Process cases often involve patent disputes between

competitors where the patent defendant brings an antitrust

counterclaim, and the thrust of the counterclaim is that the

patent suit, if successful, resulting in imposition of an injunc-

tion, would harm competition by wrongfully excluding the

defendant’s product from the market. The Federal Circuit’s

2016 decision in TransWeb v. 3M Corp.8 addressed this type

of scenario, but it, has spawned considerable confusion in

subsequent cases—confusion that, once again, could lead

to watered-down proof standards out of step with what the

Supreme Court appears to have intended.

Finally, another area in need of clarity relates to important

questions of knowledge and intent. Walker Process requires

both fraudulent patent procurement and subsequent pat-

ent enforcement. There is no dispute that Walker Process

plaintiffs must demonstrate knowing and willful fraud at

the point of patent procurement, but must they also prove

that the defendant knew of the fraud at the time the patent

was later enforced? If so, when if ever can such knowledge