By Jeffrey Toobin, Doubleday, New York, NY 2012, 325 pages, $28.95

As a sophisticated chronicler of the U.S. Supreme Court, the lawyer-journalist Jeffrey Toobin posits that, over the years, as power has changed hands, conservatives and liberals have regularly accused each other of judicial activism. Since 2006, conservatives have held the edge in the wake of Justice Samuel Alito’s appointment to replace the retiring Sandra Day O’Connor. In his new book, Toobin examines the activism of the current conservative majority, including the epic battle over President Barack Obama’s signature political achievement, the Affordable Care Act. It is a compelling read.

In framing the debate, Toobin, perhaps too simplistically, divides the justices into two ideological camps. The conservatives (Roberts; Scalia; Kennedy; Thomas; Alito) are “textualists” who believe that if the Constitution does not indentify a right, it does not exist. They also tend to espouse “originalism,” which asserts that the words of the Constitution should be interpreted as they were understood by the framers. In the liberal camp (Ginsburg; Bryer; Sotomayer; Kagan), the justices believe in a “living Constitution,” or the idea that the meaning of the Constitution changes with the times.

Looking back over the first six terms of the Roberts Court, Toobin observes with irony that, in advocating originalism so successfully, the conservatives have demonstrated that the Constitution is indeed a “living” document which “responds to and changes with the politics of the day.”

This irony is on full display in the author’s discussion of District of Columba v. Heller (2008), in which the conservative majority, led by Justice Antonin Scalia, found that the Second Amendment protects an individual’s right to keep and bear arms. But, as noted by the author, the opinion raised the question, which arms? The majority concluded that the right extends to handguns in the home, but not if you are a felon, mentally ill, or carrying a firearm in a sensitive place. Of course, there is nothing in the Constitution which mentions these distinctions. In Toobin’s view, Scalia’s opinion in Heller is an activist “improvisation” that simply discovered a “new Second Amendment,” one which, it just so happens, is consistent with modern Republican orthodoxy. According to Toobin, Scalia showed that originalism is “just another way for justices to achieve their political goals.”

Perhaps the most surprising passage in the book is a provocative chapter entitled “The Thomas Court.” In it, Toobin tries to debunk the conventional wisdom that Justice Clarence Thomas has little influence on his colleagues. The author comments that, in 1997, it was Thomas who became the first justice in modern times to write that the Second Amendment confers a personal right to keep and bear arms. He also points out that, as far back as 2000, it was Thomas who stated in a dissent that the First Amendment prohibits campaign finance regulations. By 2010, of course, this view carried the day in Citizens United v. Federal Election Commission. Toobin observes that, although the majority opinion in Citizens United was written by Justice Anthony Kennedy, “the victory was Thomas’s.”

As in his last book on the Supreme Court, The Nine, Toobin deftly weaves into the narrative of his new book pertinent biographical information about all of the current and recently-retired justices. In the cases of justices Ruth Bader Ginsburg, Sonia Sotomayor, and Sandra Day O’Connor, this is done with particular care. As a law school classmate and friend of Justice Elena Kagan, Toobin provides interesting insights into her life and career path.

The chief protagonists of the book are President Obama and Chief Justice John Roberts. To set the stage, Toobin begins with an extensive narrative on the mistakes made by Roberts in administering the presidential oath at the inauguration and the White House’s quick action to perform a “do-over” the next day. Although this incident may have been the president’s first meaningful encounter with the chief justice, it is the least interesting portion of the book.

More effective is Toobin’s discussion of Obama’s law school years and career as a lawyer, professor, and legislator. As president of the Harvard Law Review, Obama the 3L eschewed the prime clerkships and largest law firms to go to work for a small Chicago firm that focused on civil rights and political work. As described by the author, Obama knew that he wanted a future in electoral politics and chose his own unique path to start the journey.

The last and best part of the book is devoted to National Federation of Independent Business v. Sebelius, which challenged the constitutionality of the Affordable Care Act. Toobin notes that, by the time the law was enacted in March 2010, it was a foregone conclusion that conservatives would challenge its centerpiece—the individual mandate.

According to Toobin, for two decades the idea of the individual mandate was never questioned. Newt Gingrich voiced approval for it on Meet The Press as far back as 1993. Mitt Romney used it as a centerpiece for his own Massachusetts health care reform plan in 2006. But, as explained by the author, beginning in 2009, when it became increasingly clear that “Obamacare” was coming, the illegality of the individual mandate under the Commerce Clause became an “article of faith” of the GOP.

In Toobin’s view, Chief Justice Roberts’ decision to switch sides and uphold the individual mandate as a tax was a master-stroke of genius and leadership. According to the author, Roberts realized that his conservative colleagues “overplayed their hand” in insisting that the entire statute was invalid. Appreciating that “power must be tended as well as expended,” Roberts voted to uphold the statute on narrow grounds, but agreed that the Commerce Clause placed real limits on congressional power. In so doing, Roberts incurred the conservatives’ temporary wrath, but he also preserved the Court’s reputation and likely expanded its power to rein in Congress. This maneuvering, Toobin concludes, positions Roberts as perhaps the true man of “change” over the next quarter century.

Jeffrey Winn is a partner at Sedgwick LLP.