The journalist’s savage murder exposed Saudi Arabia’s ruler as an enemy of a free press. His legacy should not stop there.

A year has passed since Jamal Khashoggi, the Saudi journalist and contributor to The Washington Post and Virginia resident, entered the Saudi Arabian Consulate in Istanbul to secure a document for his approaching marriage, only to be slain and cut to pieces, all recorded in sickening detail by Turkish secret services. Though the evidence is strong that he was killed with at least the knowledge of Crown Prince Mohammed bin Salman, the de facto ruler of the kingdom, in order to silence a sharp critic, the prince remains in the good graces of President Trump.

Mr. Khashoggi’s dismembered body, taken from the consulate in suitcases, has never been found. The trial of 11 men charged in Saudi Arabia with the killing has been slow, secretive and utterly lacking in credibility. Saud al-Qahtani, the prince’s former top aide and the alleged architect of the murder, has not been charged and has vanished. Prince Mohammed finally took “full responsibility as a leader in Saudi Arabia” for the killing, in a recent interview on CBS News’s “60 Minutes” — but only as a “buck stops here” gesture, still denying any advance knowledge or involvement.

Even after the C.I.A., a United Nations investigation, Turkish prosecutors and the United States Congress pointed fingers at Prince Mohammed, Mr. Trump ignored them all to sustain the illusion that safeguarding his “friendship” with the prince was critical to arms sales, confronting Iran, securing oil supplies and producing a Middle East peace plan that the president’s son-in-law, Jared Kushner, keeps promising to unveil. On meeting the prince at the Group of 20 meeting in Osaka, Japan, Mr. Trump was effusive in his praise. “It’s an honor to be with the crown prince of Saudi Arabia, a friend of mine, a man who has really done things in the last five years in terms of opening up Saudi Arabia,” the president said. “You’ve done, really, a spectacular job.”

Prince Mohammed has made some progress on his social reforms. Women can now drive, receive equal treatment in the workplace and travel without the express permission of a male relative. That these are significant changes testifies to how repressive the kingdom has been and remains. Some women who had worked to earn these rights remain in jail or await trial for their activism.

Still, the shameless denials of complicity in Mr. Khashoggi’s death and Mr. Trump’s callous exoneration of the prince would appear to make for a sad anniversary. But those same lies have made of Mr. Khashoggi a powerful and abiding indictment of the abuse of autocratic power and have inspired a rallying cry in defense of press freedom.

The anniversary of Mr. Khashoggi’s death was marked by an outpouring of commemorative posts on social media, gatherings outside Saudi missions around the world and a rash of articles and public notice by political leaders.

If the crown prince, who recently turned 34, thought death would silence a critic, he grossly miscalculated. The global outrage undermined Prince Mohammed’s carefully fostered image as a reformer, further eroding bipartisan support for him and the kingdom in Congress, where his brutal bombing campaign in Yemen had already generated serious questions. As the House speaker, Nancy Pelosi, put it in an NPR interview last month, “I don’t see any responsibility for us to protect and defend Saudi Arabia.”

It is unlikely that Mr. Trump, now on the defensive against impeachment proceedings, will change his mind. The time has passed for this administration to do what it should have done when an American resident was sadistically choked to death and cut apart by a purported ally. There should have been immediate demands for a credible accounting, a suspension of arms sales and a report to Congress.

Nothing justifies Mr. Khashoggi’s terrible death, but at least he need not have died in vain. Crown Prince Mohammed bin Salman stands exposed as tyrannical. Nations that value human rights and a free press — along with a future, more sensible American administration — would do well to remember Mr. Khashoggi, and seek rapid, durable political reform in Saudi Arabia.