Antonin Scalia, who died on Saturday at the age of 79, will be remembered as a giant of American law. Appointed to the U.S. Supreme Court in 1986 by President Ronald Reagan, Scalia left a lasting mark on some of the biggest and most significant issues facing the judiciary, from the debate over competing methods of constitutional interpretation to the clash over the proper role of the courts. Law students, lawyers, and judges will be grappling with Scalia's legal handiwork for decades (or more) to come.

For many Americans, Scalia will be perhaps best remembered for his caustic dissents in cases dealing with issues such as abortion rights, gay rights, and gay marriage. When the Supreme Court struck down Texas' controversial ban on "homosexual conduct" in 2003, for instance, Scalia made headlines with his statement that the Court's decision in Lawrence v. Texas was "the product of a Court that has largely signed on to the so-called homosexual agenda." Scalia did not mean that as a compliment.

Yet despite his reputation as a right-wing culture warrior, Scalia was equally outspoken in other areas of the law that are commonly (if erroneously) associated with the legal left. When it came to the Fourth Amendment and its protections against unreasonable searches and seizures, for instance, Scalia frequently led the way in rejecting the pro-government interpretations favored by state and federal law enforcement. For example, in 2014 the Supreme Court ruled that a traffic stop and resulting drug bust that occurred thanks to an anonymous telephone tip "complied with the Fourth Amendment." Scalia thought otherwise. In his dissenting opinion in that case, Scalia attacked the majority for producing an opinion that "serves up a freedom-destroying cocktail" which privileged an anonymous and uncorroborated tipster over a core constitutional right. "All the malevolent 911 caller need do is assert a traffic violation, and the targeted car will be stopped, forcibly if necessary, by the police." That ugly scenario, Scalia declared, "is not my concept, and I am sure it would not be the Framers', of a people secure from unreasonable searches and seizures."

Likewise, in his 2001 majority opinion in Kyllo v. United States, Scalia came out swinging against the federal government's use of warrantless thermal imaging to detect signs of marijuana cultivation inside of a suspect's house. "Where, as here, the Government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion," Scalia wrote, "the surveillance is a 'search' and is presumptively unreasonable without a warrant."

Justice Scalia wrote a great many influential opinions during his three decades on the Court, but the one he often said he was most proud of was his 2008 majority opinion in District of Columbia v. Heller, the landmark case in which the Supreme Court struck down Washington's handgun ban and ruled that the Second Amendment protects an individual right, not a collective one, to keep and bear arms.

Scalia was proud of Heller not only because it vindicated the Second Amendment, which until then had been in a sort of legal limbo at SCOTUS; he was also proud, as he explained to the journalist Marcia Coyle, because he saw Heller as a "vindication of originalism," the theory of legal interpretation that Scalia did so much to help popularize and establish in American law. Under originalism, the Constitution is supposed to be interpreted according to its original meaning at the time of ratification. As Scalia argued in his 1997 book, A Matter of Interpretation, "if the people come to believe that the Constitution is not a text like other texts; that it means, not what it says or what it was understood to mean, but what it should mean,… well, then, they will look for qualifications other than impartiality, judgment, and lawyerly acumen in those whom they select to interpret it. More specifically," Scalia wrote, "they will look for judges who agree with them as to what evolving standards have evolved to; who agree with them as to what the Constitution ought to be."

Unfortunately, however, it must also be said that Justice Scalia did not always practice the originalist philosophy he liked to preach. Most notably, when the Supreme Court was asked in 2010 to examine the original meaning of the 14th Amendment in the gun rights case McDonald v. Chicago, Scalia not only backtracked on originalism; he actually mocked the libertarian lawyer Alan Gura for daring to ask the Supreme Court to seriously address the original meaning of the 14th Amendment in the first place.

"What you argue," Scalia scoffed at Gura during oral argument, is "contrary to 140 years of our jurisprudence." (I interject myself here to point out that fidelity to 140 years of Supreme Court jurisprudence is not exactly the same thing as fidelity to the text of the Constitution.) "Why do you undertake that burden instead of just arguing substantive due process, which as much as I think it's wrong, I have—even I have acquiesced in it."

It was an unfortunate episode, as even Scalia's biggest fans will reluctantly concede. After all, there was Scalia, the Court's foremost advocate of originalism, falling back on questionable precedents while refusing to consider the originalist arguments that were properly presented before him in a major constitutional case. To make matters worse, Scalia announced his intentions to acquiesce in a legal approach he himself considered to be un-originalist and "wrong."

As a journalist and historian who writes frequently about the Supreme Court, I've leveled my fair share of criticisms at Justice Scalia over the years. But at the same time, I've always had great respect for his keen legal mind and pugnacious rhetorical style. For better and for worse, Antonin Scalia helped shape the course of modern American law. Even among his critics, he is sure to be missed.