Nothing exemplifies the populist quality of American democracy as much as the death penalty. It is banned by most other advanced industrialized nations, including the members of the European Union, but it persists in the United States for a simple reason: The people want it.

The death penalty has public support in some European countries as well, but those democracies are far less populist than ours. In Europe, an elite consensus trumps public opinion. Here, that rarely happens.

George W. Bush's first trip overseas as president, in June 2001, coincided with the execution of Oklahoma City bomber Timothy McVeigh. Predictably, a reporter asked the president why he supports the death penalty. Bush answered that in the United States the people rule and that the death penalty is the democratic consensus of the American people. He said that, as an elected leader, he is in no position to defy the will of the people.

The will of the people extends even to an unelected institution of government, the U.S. Supreme Court. Last week, the Court barred the death penalty for mentally retarded persons, on the grounds that "a national consensus has developed against it," in the words of Justice John Paul Stevens's majority opinion.

In the Court's view, that consensus has developed in just 13 years, since the Court voted in 1989 to allow execution of the mentally retarded. The evidence cited by the justices? The number of states that explicitly prohibit the execution of retarded persons has increased from two in 1989 to 18 today. The Court viewed the fact that democratically elected legislatures have been moving in a consistent direction as evidence that Americans now consider such punishment "cruel and unusual."

The three dissenting justices—William Rehnquist, Clarence Thomas, and Antonin Scalia—scoffed at the Court's deference to public opinion. "The results of opinion polls are irrelevant," Scalia declared. He pointed out that only 18 of the 38 states that allow capital punishment have acted to ban execution of the mentally retarded. "How is it possible that agreement among 47 percent of the death-penalty jurisdictions amounts to consensus?" Scalia asked.

Since 12 states have banned capital punishment altogether, however, a total of 60 percent of the states don't permit the execution of the retarded—a proportion that looks more like a consensus. Yet Scalia complained, "Seldom has an opinion of this court rested so obviously upon nothing but the personal views of its members."

Finley Peter Dunne's Mr. Dooley once said, "Th' supreme coort follows th' iliction returns." That it does, and in death-penalty cases, it also follows the crime rate and the public opinion polls.

Go back to the early 1960s, when the nation's homicide rate was low—about 5 murders per 100,000 persons. In 1960, California's execution of Caryl Chessman, who was convicted of kidnapping and sexual assault, brought a flood of protests. The percentage of Americans who favored the death penalty for convicted murderers reached an all-time low of 42 percent in 1966.

In its 1972 Furman v. Georgia decision, the Supreme Court struck down the nation's death-penalty laws, calling them "arbitrary" and "capricious." But the murder rate had begun to rise. By 1976, it had climbed to around 9 murders per 100,000 persons, and public support for capital punishment had risen as well, reaching 66 percent that year.

Also in 1976, the Supreme Court ruled, in Gregg v. Georgia, that new death-penalty statutes providing for two-stage trials—in which juries decide guilt, then decide punishment—were constitutional. The nation's moratorium on capital punishment ended with the 1977 execution of Gary Gilmore by firing squad.

Meanwhile, the murder rate remained high, reaching a peak of 10 victims per 100,000 people in 1980. Public support for the death penalty also continued to rise, passing the 70 percent mark. In 1987, the Court refused to invalidate capital punishment even though African-Americans are sentenced to death more often than whites. And two years later, the Court upheld the death penalty for the mentally retarded.

In the 1988 presidential campaign, the death-penalty issue helped doom Democrat Michael Dukakis, then the governor of Massachusetts. In 1992, when Democratic candidate Bill Clinton, then governor of Arkansas, allowed the execution of Ricky Ray Rector, a man with borderline retardation, it was not an issue in the presidential campaign. By 1994, public support for the death penalty reached an all-time high of 80 percent.

As prosperity spread during the 1990s, the nation's murder rate began to drop sharply, down to 5.5 deaths per 100,000 people in 2000. Public support for the death penalty dropped as well, to 66 percent.

Last week, the Court reversed its 1989 decision on executing the mentally retarded. The ruling came one month after a Gallup Poll showed that Americans overwhelmingly oppose—82 percent to 13 percent—the death penalty for those who are mentally deficient.

After the Dukakis experience, so-called New Democrats, including Clinton and Al Gore, fell into line and supported the death penalty. They read the polls—but perhaps not as carefully as the Supreme Court does.

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