Chief Justice William H. Rehnquist's death ends a judicial career that has left its mark on our constitutional law of freedom of expression and religious liberty.

On the heels of Justice Sandra Day O’Connor’s resignation, the chief justice's death opens another high-stakes vacancy on the high court. As with O’Connor’s seat, the lion’s share of the talk about the next chief justice concerns hot-button issues — abortion, the death penalty, and gay marriage. Important as those issues are, they ought not to distract the president, Senate Judiciary Committee, the American public or the nation’s press from the potential impact of Rehnquist’s successor on our First Amendment freedoms.

The Rehnquist II Court (the Court as currently constituted) has been sharing courtroom and chambers since the fall term of 1994. Since then, the Court has handed down 58 First Amendment freedom-of-expression opinions in matters involving religious speech, association rights, Internet regulation, government-employee expression, indecent speech, commercial expression, telemarketing, prisoners’ speech, campaign-finance laws, hate speech, and various kinds of zoning laws affecting free speech, among others.

In those cases, free-speech claims were sustained about half the time. That record contrasts sharply with the Court’s actions in the past three terms, during which it denied such First Amendment claims in 13 of its 15 free-speech opinions. Had it not been for a minor victory this year in a defamation case involving the late Johnnie Cochran (Tory v. Cochran) and a 5-4 ruling last year in an Internet case (Ashcroft v. ACLU II), all of the free-speech claims for the last three years would have lost. Still, the high number of nearly consecutive denials of First Amendment claims is unprecedented in the Court’s modern history. At no other time in the past half-century has that happened.

In the last decade — the period during which the current Court has been together — William Rehnquist often cast the deciding vote for a split Court in First Amendment cases involving government funding of religion, religious displays, free exercise of religion, free-press protections, campaign-finance laws, commercial speech, and sexual expression.

Such cases illustrate how Rehnquist’s vote has tipped the balance of freedom in First Amendment cases. Moreover, the chief justice assigns majority opinions whenever he is in the majority, which often determines the scope of any given ruling.

Rehnquist’s First Amendment record is both practically important and historically significant. During his 33 years on the Court, first as an associate justice and then as the chief justice, Rehnquist authored 71 freedom-of-expression opinions, 29 of which were majority opinions. The vast majority of those opinions were hostile to the free-speech claims raised. On the religion side, Rehnquist authored 23 First Amendment opinions, seven of which were majority opinions for the Court. Issues in which his successor might have the same significant, even decisive, impact include no fewer than six areas of First Amendment law.

In the area of religious displays, the Court recently handed down two important First Amendment cases involving challenges to religious displays situated on government property. One case concerned the constitutionality of a display of a Ten Commandments monument on the grounds of the Texas Capitol, and the other concerned framed copies of the commandments on the walls of Kentucky courthouses. In the first case, Van Orden v. Perry, Rehnquist wrote for the plurality in upholding the placement of a Ten Commandments monument on public land. In the other case, McCreary v. ACLU of Kentucky, the Court disallowed the placement of the Ten Commandments in a courtroom with Rehnquist in the dissent. The diverse rulings assure future litigation in which the Rehnquist-successor vote will be decisive.

There is also the matter of government funding of religion: In 2002, the Court, by a 5-4 vote, lowered the wall separating church and state when it upheld government-funded tuition vouchers for private schools, primarily religious schools. Rehnquist authored the majority opinion in that case. Rehnquist’s replacement could thus play a key role in determining the constitutionality of government funding of any variety of “faith-based” initiatives in which federal or state dollars go to religious organizations.

Another important issue concerns the free exercise of religion. In 1990, a divided Court, ruling in Employment Division v. Smith, severely limited the constitutional protections afforded to Americans under the First Amendment’s free-exercise clause. The majority decision, with which Rehnquist agreed, shocked many in the religious world and prompted Congress to enact (almost unanimously) the Religious Freedom Restoration Act, which in 1997 was declared unconstitutional, in major part, by the Court’s ruling in City of Boerne v. Flores. Today, that 1990 ruling remains the Supreme law of the land — but that could change if a new member of the Court joined with other justices to reconsider that controversial precedent.

On the free-speech side of the equation, there is the issue of the constitutionality of campaign-finance laws. What limitations, if any, can federal and state lawmakers place on campaign contributions? Since Rehnquist came to the Court in 1972, the justices have rendered 13 First Amendment opinions concerning this controversial issue. Two years ago a divided court, with the chief justice in the majority, upheld a variety of campaign-contribution restrictions in McConnell v. Federal Election Commission. The future of campaign-finance reform and attempts to limit the “influence of money” could thus hinge on the vote of the next person selected to sit on the high court.

The question of the extent to which government can regulate sexual expression is always controversial. For example, to what extent can state and local officials employ novel and sweeping zoning laws to combat the allegedly deleterious effects of “adult” entertainment businesses? Three years ago the justices split 5-4 in favor of granting local officials wide latitude in this area. Rehnquist, who cast the deciding vote in that case, City of Los Angeles v. Alameda Books, had long argued that such zoning measures serve “a substantial governmental interest” and should therefore be given great deference.

Finally, there is the matter of commercial speech. The Rehnquist Court has gone to considerable lengths to protect commercial expression, typically made by corporate speakers, to advertise various products ranging from alcohol and tobacco to casino gambling and lottery tickets. Early in his career on the Court, Rehnquist was a stern critic of the idea of protecting commercial expression. More recently, however, he had shown some sympathy for it. For example, in 2001 he provided the fifth vote to strike down an outdoor tobacco advertising law that banned such signs or on-site displays anywhere within 1,000 feet of schools or playgrounds. That ruling in Lorillard Tobacco Co. v. Reilly, and other cases like it, emboldened alcohol and tobacco advertisers as well as others who trade in legal but harmful products. Whether that trend will continue could depend on the vote of the next person nominated to sit on the Court.

All of these issues reach deep into the lives of Americans. Now that the chief justice is gone, there needs to be a public airing of First Amendment issues in the nomination and confirmation process so that ample consideration is given to safeguarding our most fundamental freedoms, especially those recognized in the First Amendment.

Ronald Collins, a former Supreme Court judicial fellow, is a scholar at the First Amendment Center in Arlington, Va. An earlier version of this article appeared last year in the Miami Herald newspaper.