Paul MacMahon


Paul MacMahonEmail: P.H.Macmahon@lse.ac.uk
Administrative support: Michele Sahrle
Room: New Academic Building 6.02A
Tel. 020-7955-6632

Paul joined the LSE as an Assistant Professor in 2014. Before that, he studied at Oxford (BA, BCL, DPhil) and Harvard (JD), worked as a lawyer in New York, served as a law clerk to two American judges, and taught law at Cambridge and Harvard. A full CV is available here.
 

Research Interests

• Contracts

• Procedure & Dispute Resolution
 

      
Selected articles
and chapters in books
 

(with Deirdre Mask) 'The Revolutionary War Prize Cases and the Origins of Diversity Jurisdiction' Buffalo Law Review 63 (2015): 477-547

Why did the Framers give the United States federal courts diversity jurisdiction? This Article brings to light a crucial but forgotten source of inspiration for diversity jurisdiction, showing that previous explanations ignore the Framers’ experience judging prize case appeals during the Revolutionary War. Scholars have largely rejected the view that the Framers anticipated state bias in diversity litigation, arguing, for example, that diversity jurisdiction was designed to provide a high-quality venue for commercial disputes. Yet placing the Framers’ decision in the context of their lived experience as judges in contentious "Prize Cases" during the Revolutionary War rehabilitates the geographic bias theory. During the War, the Continental Congress relied heavily on privateers — private citizens, who, with the financial support of individual states or Congress, were authorized to capture British ships. At George Washington’s urging, the Continental Congress set up an adjudicatory committee within Congress itself, the Committee on Appeals, to resolve appeals from prize cases in the state courts. The Framers’ taste of judicial work exposed them to contentious interstate disputes — a preview of what diversity litigation would look like in the new country. We argue that this experience, almost entirely ignored by contemporary scholars, directly inspired the otherwise perplexing decision to include diversity jurisdiction in Article III.

'Good Faith and Fair Dealing as an Underenforced Legal Norm' Law Society and Economy Working Paper Series WPS 22-2014 December 2014;  Minnesota Law Review (2015) 99 (6)

American contract law includes a duty of good faith and fair dealing in the performance of every contract. The duty appears, on first reading, to authorize judges to attach sanctions whenever one party to a contract acts unreasonably towards another. But judicial practice very often falls short of such an expansive standard. This article proposes a novel interpretation of the doctrine that accommodates both the rhetoric of good faith and fair dealing and the reality of judicial enforcement. Good faith and fair dealing, the article contends, is an underenforced legal norm. The duty is valid as a legal norm to the fullest extent, even though courts engage only in partial enforcement of that norm. This article is the first to bring the idea of underenforced legal norms into private law, drawing on the extensive literature on underenforced legal norms in constitutional law, and on analogous ideas in corporate law. The article explores the reasons why legislatures and courts might want to announce a duty whose scope extends beyond what the courts enforce. In private law, as elsewhere, the underenforcement idea allows courts to lend their expressive support to the broader norm while avoiding the negative side effects that attempted full enforcement would entail.

Book Review: Revisiting the Contracts Scholarship of Stewart Macaulay (Jean Braucher, John Kidwell, and William C. Whitford, eds. 2013) Modern Law Review (2015) 78 (4) pp.708-713

'The Inquest and the Virtues of Soft Adjudication' (forthcoming, Yale Law and Policy Review, 2015)

An inquest is a quasi-judicial proceeding resulting in a verdict as to the cause and manner of a suspicious or unusual death. Inquests are an important feature of most common-law legal systems, but have been ignored by American legal scholars for decades. In fact, inquests continue to be held in some American localities. Inquests are intriguing partly because they are inquisitorial proceedings in stereotypically adversarial common law systems. Their determinations do not directly affect anyone’s legal rights or duties, but may be highly consequential. This Article uncovers the American inquest, and explores the case for revamping and reviving the institution. Precisely because their verdicts do not carry coercive consequences, the Article contends, inquests can aim more squarely than other legal proceedings at establishing the truth about a contested event. Accordingly, they have significant advantages in the furtherance of important societal goals, including accountability for wrongful deaths, the collection and dissemination of information about risky activities, and helping the deceased’s family come to terms with a traumatic death. The Article focuses on one particular area where suitably designed inquests could be particularly effective: deaths at the hands of police and prisoner officers. More broadly, the inquest is an example of legal institutions providing non-binding-yet-formal-pronouncements about past events, a phenomenon I call "soft adjudication."

'Proceduralism, Civil Justice, and American Legal Thought' 34 University of Pennsylvania Journal of International Law 545-610 (2013)
 

American legal scholars spend a large proportion of their time debating and theorizing procedure. This Article focuses on American proceduralism in the particular field of civil justice and undertakes a detailed comparison with England, where procedural questions receive little academic attention. It finds that procedure is more prominent in America partly because Americans have been more willing than others to use private litigation as a tool for regulation. More significantly, procedural questions necessarily occupy more space in American debates because authority over civil justice is unusually dispersed among different actors; procedural rules allocate power among these actors. But American proceduralism runs deeper than these surface explanations allow, and a full account requires an examination of the history of American legal thought. I trace contemporary American proceduralism to a counter-intuitive source: the emergence of Legal Realism in the 1920s and 1930s.

'Self-Service Search Warrants and International Terrorism' 1 Ir. L.J. 2 (2012)

In February 2012, the Supreme Court of Ireland invalidated a long-standing statutory provision that allowed the police to help themselves to search warrants in terrorism cases. Though the case has far-reaching practical consequences and theoretical implications, the Supreme Court’s written decision was relatively spare. The aim of this comment is to deepen the discussion. To that end, I examine the purposes of search warrant requirements as part of a legal regime for protecting privacy against government intrusion. I also discuss the judicial power to reject counterterrorism measures approved by the elected branches of government. Finally, I connect the Supreme Court’s decision to fundamental and recurring questions about the Irish judiciary’s level of trust in law enforcement authorities.