Justice Antonin Scalia, who died suddenly Saturday at age 79, served the conservative cause probably greater than President Ronald Reagan could have imagined when appointing him to the U.S. Supreme Court in 1986.

As the first Italian-American justice, he made immediate history. However, it is Scalia’s legal philosophy of constitutional originalism — basing the court’s interpretation of the Constitution on divining the intentions of those who wrote and ratified it — that is writ large in many of the high court’s decisions of the last three decades and influences the reasoning of federal appeals courts.

Originalists act as if they have found some great truth. The reality is that the Constitution and its amendments were the result of compromises and those who developed the text disagreed on how to interpret the language to specific cases. The legal decisions of originalists, Scalia among them, produce no more certainty or any less room for subjective elucidation than do the decisions of the devotees of the leading opposing theory that seeks to understand the Constitution as a living document that the court should interpret in light of contemporary values and evolving traditions.

What originalism does do is discourage change and social progress.

With his opposition to gay marriage and to abortion rights, his tolerance of religion in the public sphere, his view of affirmative action policies as reverse discrimination, his hostility toward environmental regulations, and in finding that campaign finance restrictions violate free speech, Scalia well served the conservative ideology.

Give Scalia his due. In his most significant opinion written for the majority — District of Columbia v. Heller that struck down Washington, D.C.’s ban on handguns — Scalia brilliantly dug deep for historic sources to justify ignoring the preamble of the Second Amendment. That is the part declaring that the purpose of the amendment is to protect a well-regulated militia. Pushing past the preamble, Scalia and the 5-4 majority reached their desired conclusion that the second part of the amendment created an individual right to bear arms for self-defense.

Scalia was fully confident in his majority opinions and often disdainful in his minority dissents, stating that Justice Anthony M. Kennedy’s majority opinion finding a constitutional protection for same-sex marriage was “couched in a style that is as pretentious as its content is egotistic.”

But he did not always make conservatives happy. He ruled with the majority in 1989 in correctly concluding that burning the American flag in protest, as disdainful as that may be, is protected by the First Amendment. He was a strong advocate for defendant rights under the Sixth Amendment, sometimes to the irritation of law-and-order types.

Scalia was influential, memorable and interesting. History will not easily forget him.