[James MacGregor Burns is professor of government emeritus at Williams College and author of “Packing the Court: The Rise of Judicial Power and the Coming Crisis of the Supreme Court.’’]

WHEN THE Senate Judiciary Committee begins confirmation hearings for Judge Sonia Sotomayor tomorrow, Americans will have an opportunity to evaluate her qualifications and judicial philosophy. But it may be more illuminating for us to reexamine the powers of the Supreme Court itself - especially its power to declare unconstitutional laws that are enacted by the democratically elected branches of the federal government. In the Supreme Court’s ruling of June 22 on a challenge to the landmark Voting Rights Act, Justice John Roberts wrote that finding an act of Congress unconstitutional is the “gravest and most delicate’’ task the justices have. Grave and delicate, indeed.

Let us for a few minutes think like true “originalists’’ who respect the original intentions of the framers of the Constitution when they drew up their blueprint for American government in 1787.

Why did the framers give the court that extraordinary veto power? The answer: They did not. This was not an oversight. Judicial supremacy had no place in their carefully calculated blueprint for checks and balances.

No branch of government was to be supreme. The framers, many of them lawyers, were meticulous thinkers. They did not include a judicial veto because they did not want it in the hands of unelected lifelong appointees.

How, then, was judicial supremacy established? By a masterstroke at the hands of the most brilliant chief justice in American history, John Marshall. A staunch Federalist hostile to the Jeffersonian Republicans, Marshall saw an opportunity in an otherwise routine case in 1803, Marbury v. Madison, to “bootleg’’ judicial review into the Constitution. But in his quest to make the Supreme Court the ultimate arbiter of the Constitution, he faced a daunting obstacle - the Jeffersonians would laugh in his face if his court tried to strike down a bill passed by Senate and House Republicans. Marshall’s solution? His court invalidated a minor act that had been designed to give the Supreme Court a routine, essentially administrative power.

The Jeffersonians were outfoxed. Just as Marshall hoped, this ostensibly self-limiting act on the part of the Supreme Court actually bestowed upon the court its precedent for future vetoes. But it was not until decades after Marbury, in the Dred Scott case in 1856, that the court struck again, in effect invalidating the Missouri Compromise and helping to precipitate the Civil War. And after the war, despite new constitutional amendments guaranteeing rights of due process and equal protection to all, those new rights became the province of a reactionary Supreme Court that again and again limited them. For how much longer, in an increasingly democratized country, would the nation tolerate this extra-constitutional judicial power?...