Originally published in The Wall Street Journal.
Many conservatives are angry with Chief Justice John Roberts, whose decisive vote in late June not only sustained a disastrous health-care law. It also interpreted the Constitution to permit Congress to penalize behavior through its taxing power that it cannot control through its power to regulate commerce.
Magnifying the harm is a CBS News report—and informed suspicions from a number of sources—that Chief Justice Roberts initially voted to strike down the law but switched in the face of veiled threats from President Barack Obama and concerns about the court's reputation and his own.
Some conservatives were also disappointed that Chief Justice Roberts joined fellow conservative Justice Anthony Kennedy and the four liberal justices earlier in June in striking down portions of Arizona's immigration law. They considered the ruling a blow against federalism.
The upshot is that Chief Justice Roberts has become a "swing" justice on the Supreme Court—along with Justice Kennedy, who has occupied the swing position held by Justice Sandra Day O'Connor until she was replaced by conservative Justice Samuel Alito in 2006. The court now is composed of three solid conservatives and four solid liberals, with Chief Justice Roberts and Justice Kennedy leaning conservative.
Even that mixture makes the current court the most conservative in nearly a century. But it also means that the replacement of a single conservative justice by President Obama in a second term would turn the court sharply to the left.
The ObamaCare ruling highlights the stakes. Chief Justice Roberts joined the liberal justices in finding that the penalty imposed on individuals who refuse to sign up for government-prescribed health insurance is a permissible tax. But he sided with his fellow conservatives in holding that the mandate to buy insurance itself exceeded Congress's power to regulate interstate commerce. Inactivity, the court held, is not commerce.
By contrast, the liberal justices argued that anything that even indirectly affects commerce (which amounts to everything) can be regulated. With the replacement of one conservative justice by a liberal, congressional power under the Constitution's Commerce Clause will be boundless.
By holding the line in June, then, the conservative majority ensured, at least for now, that the power of the national government remains limited. That portion of the health-care decision continues an important trend in which the court has set boundaries on federal regulatory power that had been erased during the New Deal.
Over the past two decades of its conservative majority, in fact, the court has reined in government power and protected important individual rights in a number of areas, almost always in 5-4 votes divided along conservative/liberal lines. Among them:
- First Amendment. In its Citizens United decision in 2010 and its ruling the next year in Free Enterprise Club v. Bennett, which struck down Arizona's scheme providing public "matching funds" to candidates, the court has protected the right to vigorously participate in political campaigns.
- Second Amendment. The court has recognized an individual right to keep and bear arms, which the four liberal justices would have extinguished, and which now hangs by the thread of a single vote.
- School choice. Last month marked the 10th anniversary of the 5-4 Zelman v. Simmons-Harris ruling upholding the constitutionality of issuing school vouchers that can be used for tuition at parochial schools, among others. This was the case that the court's liberal dissenters preposterously predicted would unleash religious strife akin to that in Bosnia and Northern Ireland.
- Property rights. The conservative majority has ruled that some excessive property regulations—such as forced dedication requirements in return for development permits—are unconstitutional. It has also ruled that regulations that destroy property value—such as ones that essentially forbid development—require compensation. But Justice Kennedy joined the liberal majority in the infamous 2005 Kelo decision upholding the use of eminent domain for private purposes.
- Racial preferences. The court has restricted the use of racial preferences and may forbid them altogether in Fisher v. University of Texas, which will be argued before the court next term. The liberal justices recognize few limits on the use of race for social-engineering purposes.
- Federalism. In several cases, the conservative majority has expanded state autonomy and limited the federal government's power to regulate states. These include Horne v. Flores, upholding Arizona's English-only law in 2009; Chamber of Commerce v. Whiting in 2011, upholding Arizona's law penalizing employers who hire illegal immigrants; and Northwest Austin Utility District v. Holder, a 2009 decision allowing a Texas utility district to opt about of Section 5 of the Voting Rights Act, which requires many states and local entities to obtain Justice Department permission to make any changes affecting voting.
The court's conservative majority so far has endured for 21 years, since Justice Clarence Thomas replaced Thurgood Marshall. Since then, there have been six appointments to the court. None, however, has affected the court's balance, with two conservatives replacing conservatives and four liberals replacing liberals.
That may be about to change. Three justices—liberal Ruth Bader Ginsburg and conservatives Antonin Scalia and Justice Kennedy—will reach their 80s during the next presidential administration. So whoever wins in November likely will have the chance either to reinforce the conservative majority, or to alter the court's balance for the first time in nearly a generation.
The stakes never have been higher. First, because as human longevity increases, lifetime tenure has grown increasingly valuable. The average tenure of a Supreme Court justice today is 25 years—spanning more than six presidential terms. And presidents are catching on, naming ever-younger justices. If the newest justice, Elena Kagan, serves for all of her current life expectancy, she will remain on the court until 2045.
Second, the science of nominating philosophically consistent justices has grown more precise. In the past, presidents from Abraham Lincoln to Franklin Roosevelt to Richard Nixon tried to pack the court with reliable fellow-thinkers, with decidedly mixed success. Dwight Eisenhower famously remarked that his two biggest mistakes both served on the Supreme Court (Earl Warren and William Brennan). John F. Kennedy appointed Byron White, who turned conservative toward the end of his tenure, and George H.W. Bush appointed David Souter, who was liberal from day one.
These days, however, justices are carefully chosen on the basis of long philosophical track records. Indeed, most Supreme Court justices today remain more true to their principles than the presidents who appoint them.
A Republican president may spend like a drunken sailor or destroy capitalism in order to save it, and a Democrat may bail out Wall Street and fail to bring the troops home. But they will never disappoint their respective bases on Supreme Court nominations.
All of this underscores that in terms of lasting importance, the power to control Supreme Court nominations is the grand prize in the coming presidential election. Long after Barack Obama and Mitt Romney fade in our memories, the Supreme Court justices one of them appoints will still be rendering the rulings that determine the future course of our nation.
Mr. Bolick is vice president for litigation at the Goldwater Institute and author of Two-Fer: Electing a President and a Supreme Court, published in April by the Hoover Institution