In the days leading up to Barack Obama’s inauguration, John Roberts practiced administering the oath of office so much at home that his wife deadpanned, “At this point the dog thinks it’s president.” And yet the White House felt compelled to redo the ceremony, in private, after a verbal slip. The chief justice wasn’t entirely at fault. The transition team had neglected to pass along a message from him, helpfully breaking the oath into separate lines. So when Obama jumped the gun, Roberts got rattled and transposed the word “faithfully.”

The question of faithfulness to the Constitution has highlighted sharp divisions between these two men. But in his new book, Jeffrey Toobin argues that their expected roles are reversed, with Obama as the Tory and Roberts the Jacobin.

Toobin, a legal analyst for CNN and The New Yorker, examines recent Supreme Court decisions that demonstrate a pattern of wanton indifference to stare decisis, the venerable admonition to judges to think hard before scuttling prior rulings. The president’s enemies turned feral when their beloved chief justice cast the decisive vote to save the Affordable Care Act, but these ideological ingrates don’t realize this was a one-shot deal. Since he took the center chair, Roberts has handed them a slew of victories. And progressives should stock up on Xanax: he’s only just begun. “Roberts has the luxury of playing a long game,” Toobin writes, “and he is.”

The Oath is the sequel to The Nine, Toobin’s bestselling account of the Rehnquist Court. Overlap is inevitable. Again we hear about the justices’ backgrounds and idiosyncrasies: David Souter’s distaste for modern conveniences, Ruth Bader Ginsburg’s pioneering litigation in the field of sex discrimination, Clarence Thomas’ lingering bitterness over his confirmation hearings, etc. The uninformed are thus duly provisioned with context. Less acceptable, however, is Toobin’s occasional heavy-handed repetitiveness; he keeps bringing up points that have already been well-addressed, as if fearing the reader suffers from short-term memory loss.

Nevertheless, he is a reliable and astute guide through the thicket of legalese. He describes rollbacks in three areas: gun control, abortion and campaign finance restrictions. “Citizens United” exsanguinated the latter. Toobin considers this ruling, hitherto the most significant of the Roberts Court, a blatant partisan overreach, the worst since the ad hoc travesty that delivered the presidency to George W. Bush. Under the umbrella of free speech, the Court declared open season on elections; corporate rainmakers could flood the 1-percent-loving Republican Party with GDP-sized contributions, an unmatchable advantage over the Democrats.

“Citizens United” was Roberts’ wake-up call to the nation: This ain’t your daddy’s Supreme Court, he was saying. For much of its history, Toobin informs us, the Court has been “dedicated to obstructing legislative initiatives that might protect the nation’s less powerful citizens.” After Franklin D. Roosevelt appointed eight out of nine justices, it tilted slightly to the left. But not until Earl Warren donned the chief justice’s robe did its heart truly bleed.

Roberts is now busy cauterizing it with a blow torch. He uses his mastery of judicial procedure to throw out underdog-friendly cases. But his four conservative colleagues —Thomas, Antonin Scalia, Samuel Alito, Anthony Kennedy — have given him the power to shape the future by erasing the past. Sometimes Kennedy steps off the reservation — on such issues as gay rights, torture and immigration — but overall he too would like to see the Court return to a pre-New Deal mindset.

Where does this leave President Obama, then? Toobin praises his Supreme Court appointments, Sandra Sotomayor and Elena Kagan, but criticizes his laxness in filling vacancies on the federal bench. Public outrage should have been whipped up against Senate obstructionists, he believes. But the president is, at heart, a conservative; he treads carefully and aims to preserve the status quo, unlike some Republicans who would dismantle everything and start from scratch.

If reelected, Obama may get the opportunity to pick a third or even fourth justice: Ginsburg has been ill, and Breyer is tired of issuing dissenting opinions. If Mitt Romney wins and either Ginsburg or Breyer calls it quits, the vital center in American politics will not hold. Roberts is poised to move mountains; next year, he will likely end affirmative action and weaken enforcement of the Voting Rights Act. Imagine the tectonic shifts with another right-wing radical on his team. It depends on who faces him, with his hand raised, at the stroke of noon on Jan. 20.

Ariel Gonzalez teaches English at Miami Dade College.