Last year the Obama administration updated Washington's official position on what forms of expression are legal. "Whether a given category of speech enjoys First Amendment protection," Solicitor General Elena Kagan argued in U.S. v. Stevens, "depends upon a categorical balancing of the value of the speech against its societal costs."

In April the Supreme Court treated this cost-benefit approach to the Bill of Rights' very first proscription on federal power with the derision it deserved. Writing for an 8-to-1 majority that overturned a 1999 law restricting depictions of animal cruelty, Chief Justice John Roberts called Kagan's argument "startling and dangerous." The First Amendment, he explained, "does not extend only to categories of speech that survive an ad hoc balancing of relative social costs and benefits. The First Amendment itself reflects a judgment by the American people that the benefits of its restrictions on the Government outweigh the costs."

Kagan's claim was a timely reminder that government, everywhere and always, seeks to balance controversial speech against various counterweights: national security, concerns about the influence of money in politics, the desire to protect society from the coarsening effects of obscenity. And if a child plays any role in the cost-benefit calculation—when school safety is supposedly at issue, or in a custody battle—the counterweight is deemed very heavy indeed.

Many, perhaps most, restrictions on speech are popular when they're enacted. The reasons aren't hard to understand. When your overriding goal is to prevent something most decent people find abhorrent (child pornography, corporate malfeasance, terrorism), and when distasteful speech is seen to obstruct that goal, that's when people start to say, "Normally, I'm a First Amendment absolutist, but…"

So it was that the putative free speech champions on the New York Times editorial board praised the Supreme Court's "respectful treatment of the First Amendment" in the Stevens case but in the very same editorial pilloried the Court's 5-to-4 ruling in Citizens United v. FEC, which rejected federal censorship of a political documentary produced by a conservative group organized as a nonprofit corporation. Why the support for crush videos but not for corporate-sponsored political speech? Because legalizing the latter "opened the floodgates for big business and special-interest dollars to overwhelm American politics." And catastrophic floods are no time for arcane constitutional debates.

Fortunately, the Framers understood that political passion too often trumps principle and that the natural reflex of people with power is to accumulate more. That is why the courts' enforcement of constitutional restrictions is so important.

If you read one article about the Supreme Court this summer, make it Associate Editor Damon W. Root's cover story, "Conservatives v. Libertarians." While the mainstream press continues to shoehorn all legal philosophies into a right-left spectrum, Root explores an underappreciated but equally important fault line: the split between conservatives who champion "judicial restraint" and libertarians willing to toss out even decades-old precedents if they flout the Constitution.

As Root's article details, the tensions between these two tendencies can be found not only between established wings of the conservative legal movement but even within the minds of individual justices, especially Antonin Scalia. How those struggles play out on the Roberts court—including the unsettled question of Roberts' own appetite and justification for overturning precedent—will go a long way in determining legal safeguards at a time of enormous government expansion.

This battle has repercussions far outside the courtroom, with echoes every time someone offers a consequentialist argument for limiting our freedom of expression. The patron saint of conservative judicial restraint, Robert Bork, shares an important trait with The New York Times and other censorious voices on the left: a belief that citizens are powerless to protect themselves from the consequences of unpleasant speech.

"Liberty in America can be enhanced by reinstating, legislatively, restraints upon the direction of our culture and morality," Bork wrote in National Review in 2005. "Censorship as an enhancement of liberty may seem paradoxical. Yet it should be obvious, to all but dogmatic First Amendment absolutists, that people forced to live in an increasingly brutalized culture are, in a very real sense, not wholly free."

Seeing individuals as powerless in the face of choice, or as empty vessels too easily overwhelmed by nefarious content, is a key component of paternalism. This view denies citizens their basic agency and autonomy, reinforcing the long-discredited but still popular notion that mass behavior is dictated from the top down.

"What we are facing," President Barack Obama hyperbolized about Citizens United in early May, "is no less than a potential corporate takeover of our elections. What is at stake is no less than the integrity of our democracy." It was a gross if common overestimation of corporate influence on our minds, and a grosser underestimation of the American people's ability to think for themselves. Such a mindset explains how MSNBC blowhard Keith Olbermann could say something as profoundly stupid as his comment that Citizens United "might actually have more dire implications than Dred Scott v. Sandford."

A similar note has been repeatedly sounded during the last two years of liberal anxiety over Tea Parties and allegedly resurgent right-wing violence. In April, on the 15th anniversary of the Oklahoma City bombing, former President Bill Clinton wrote a New York Times op-ed that echoed his unforgivably cynical reaction to the bombing when it transpired. Then as now, he linked the murderous act with the words of nonviolent political commentators.

The bombers, Clinton wrote, "took to the ultimate extreme an idea advocated in the months and years before the bombing by an increasingly vocal minority: the belief that the greatest threat to American freedom is our government, and that public servants do not protect our freedoms, but abuse them.…As we exercise the right to advocate our views, and as we animate our supporters, we must all assume responsibility for our words and actions before they enter a vast echo chamber and reach those both serious and delirious, connected and unhinged."

Such talk doesn't just serve the partisan purpose of marginalizing political opponents. It reflects an unseemly condescension to the consumers of political media, and it suggests a path toward censorship. Time's Joe Klein has accused several critics of Obama—including Sen. Tom Coburn (R-Okla.), Sarah Palin, Glenn Beck, and Fox News in general—not just of "hate speech" but of the more legally serious "borderline sedition." After Coburn warned that some citizens might be saying, "?'I give up on my government,' and rightly so," Klein charged that the senator's statement "comes dangerously close to incitement to violence." Needless to say, Klein wasn't talking about criminalizing dissent back in the Bush-Cheney years.

Suppressing peaceful speech to prevent potential violence is a kind of pre-emptive heckler's veto. We saw it in another context that same month, when Comedy Central heavily censored a South Park episode that depicted the prophet Muhammad. We see it when partisans try to silence the opposition and when the government weighs the costs and benefits of free expression.

The good news is that the Roberts Court so far is shaping up as a strong defender of the First Amendment. The bad news? Just before this issue went to press, Obama announced as his next Supreme Court appointment the same person who proposed that outrageous "categorical balancing" test for free speech: Elena Kagan. Here's hoping some vigorous political speech influences the selection process.

Matt Welch (matt.welch@reason.com) is editor in chief of reason.