While the Senate Judiciary Committee peppered U.S. Supreme Court nominee Elena Kagan with questions two weeks ago, the really important news happened at the Court itself. On Monday morning, June 28, the Court issued the most important fundamental-rights decision since 1973, when Roe v. Wade created the right to abortion. In McDonald v. City of Chicago, the Supreme Court for the first time ever applied the Second Amendment to state and local governments.

Certain to be lost in the discussion of McDonald is the fact that, as a peculiar consequence of the Court’s decision-making rules, Chicago, which lost the case, actually prevailed on each of the decisive issues needed to win. The outcome in this landmark decision, which will dramatically alter legal policy in vital urban centers, is less a function of grand theories of constitutional law than the inner workings of the Court.

In 2008, the Supreme Court held that the Second Amendment protects an individual’s right to own a handgun. That decision was limited to federal territories, such as the District of Columbia or Guam. McDonald v. City of Chicago asked whether the Second Amendment also applies to state and local governments. Constitutional law professors used to tell students that almost the entire Bill of Rights applies — or is “incorporated” — against state and local governments. Under this doctrine, not only is the federal government prohibited from restricting freedom of speech or imposing cruel and unusual punishment, but state and local governments are as well. McDonald addressed whether the individual right to gun ownership should be one of these incorporated rights.

Otis McDonald, who wanted to own a handgun contrary to Chicago law, offered two arguments supporting his position that the Second Amendment protected him. First, McDonald argued that the Second Amendment is a fundamental right applicable to Chicago through the 14th Amendment’s due process clause. Five justices accepted Chicago’s contrary argument that this clause does not incorporate the Second Amendment. Second, McDonald argued that a separate 14th Amendment provision, the privileges or immunities clause, covers the Second Amendment right. Eight justices accepted Chicago’s contrary argument that it does not.

With separate majorities rejecting each of McDonald’s arguments for applying the Second Amendment to Chicago, it would seem that McDonald should have lost. However, the Court does not make its decisions based upon the preceding logic. Although the justices’ written opinions explain the rationale of the authors, or those who join them, the Court as a whole decides the case based instead on the votes of individual justices on the ultimate choice of whether to affirm or reverse. In McDonald, five justices voted to apply the Second Amendment to Chicago, but those justices divided over two opposite — and inconsistent — rationales.

Writing for a plurality of four, Justice Samuel Alito Jr. determined that the Second Amendment applied to Chicago through the due process clause. However, Alito’s plurality found that the other argument, based on the privileges or immunities clause, was foreclosed by 150 years of precedent.

Writing only for himself, Justice Clarence Thomas expressed opposite reasoning on both issues. Thomas rejected the due process argument but reasoned that the long-standing precedent that all but eliminated the privileges or immunities clause was mistaken and that this once moribund clause should be revived.

This decision reflects deep divisions on the Court and the influence its internal decision-making rules have in affecting legal doctrine. Chicago prevailed on each argument as to why the Second Amendment should not apply to state and local governments. Nonetheless, the Court concluded the Second Amendment applied by cobbling together fractured positions, none of which sufficed to persuade a majority. We do not suggest that the Court should alter its decision-making rules. We do, however, believe that this case and others that reflect the complex inner workings of a sometimes badly fractured Court demonstrate the importance of understanding not just jurisprudential theories, but also how the various views of the justices come together to form constitutional doctrine.

During Kagan’s confirmation hearings, members of the Senate Judiciary Committee questioned her on these recent Second Amendment rulings. Another important line of inquiry would have been about her role as a potential consensus builder. What the Court needs is someone who can forge consensus, not only by uniting with her natural allies but also by occasionally persuading those on the other side. An effective coalition builder might have avoided the McDonald outcome by convincing at least one conservative member of the Court of the importance of an agreed-upon rationale as a precondition to upsetting long-standing urban policies throughout the United States concerning gun control. A meaningful hearing would have shown whether Kagan is likely to have the vital skills needed to ensure that outcomes are based upon compelling reasoning rather than determined by the peculiarities of vote counting.

David S. Cohen is an associate professor of law at Earle Mack School of Law at Drexel University and author of “The Precedent-Based Voting Paradox” in the Boston University Law Review (2010). Maxwell Stearns is a professor of law and the Marbury Research Professor at the University of Maryland School of Law, and co-author of Public Choice Concepts and Applications in Law (West 2009).