President Trump, right, shakes hands with Saudi Arabia's Crown Prince Mohammed bin Salman in the Oval Office in March 2018. (Jonathan Ernst/Reuters)

Fred Ryan is publisher and chief executive of The Post. He served as assistant to President Ronald Reagan.

Six months ago today, a man on the brink of his greatest happiness walked into Saudi Arabia’s Consulate in Istanbul while his wife-to-be watched from the gate. He went there at the direction of Saudi officials to retrieve documents needed for his upcoming marriage. But it was a carefully set trap. Lying in wait were more than a dozen trained Saudi agents, who murdered him and then brutally dismembered his body.

Post contributing columnist Jamal Khashoggi did nothing to deserve this gruesome fate. He was attacked on orders of Saudi Arabia’s crown prince, Mohammed Bin Salman, simply for doing a journalist’s job: telling the truth.

Now, half a year after this heinous act shocked the world, it is worth taking stock of what has been done in response — and what has not.

The Saudis have adopted a strategy of evasion. They still have not produced Khashoggi’s body, preventing his family from holding a proper Islamic funeral. The regime has scapegoated expendable officials, seeking to quell international furor by staging a sham trial. The coordinator of the operation that killed Khashoggi, Saud al-Qahtani, remains free — and is actively advising the crown prince. Meanwhile, Mohammed bin Salman has jetted around the world, high-fiving Russian President Vladimir Putin, getting chummy with China, and rubbing elbows with other world leaders as part of a global tour to rehabilitate his reputation.

The international community, to its credit, has taken a principled stand for press freedom and human rights. Last month, 36 countries, including all 28 European Union members, banded together at the U.N. Human Rights Council to “condemn in the strongest possible terms” Khashoggi’s murder and to call on the Saudis to cooperate with an ongoing U.N. inquiry. A number of Western democracies have suspended political visits to Saudi Arabia, curtailed arms sales and withheld other gestures of support for the regime.  

And what about the United States, long the standard-bearer for liberty around the world?

The dedicated professionals in our intelligence services have done their jobs. They investigated swiftly and thoroughly, concluding — with high confidence — that the crown prince was indeed behind Khashoggi’s killing.

Congress is doing its job, too. On a bipartisan basis, it voted to withhold support for Saudi Arabia’s war in Yemen, investigated the U.S. response to the murder, and moved to restrict the transfer of nuclear technology to the Saudi government. In October, senators invoked the Magnitsky Act, allowing the United States to impose penalties on Saudis who violated human rights through their involvement in Khashoggi’s killing.

But the Trump administration is a far different story. White House officials have issued critical words and slaps on the wrist, but they’ve stopped short of imposing meaningful penalties. They have stonewalled and obfuscated, brushing aside the CIA’s findings to continue business as usual with the crown prince. This “I see nothing!” approach has meant looking away not only as the Saudis killed a prominent journalist, but also as the regime jails women for demanding basic liberties, tortures business leaders and terrorizes citizens into submission.

Sadly, the most submissive figure in this story is President Trump. Even after irrefutable evidence came to light showing the Saudis had lied about Khashoggi’s death, Trump proclaimed Mohammed bin Salman a “great ally” and protested that the crown prince might well be innocent. Perhaps most egregiously, Trump has abdicated the responsibilities of his office, refusing to comply with the Magnitsky Act’s requirements that the administration present its findings on the Khashoggi case to Congress.  

In this impotent response, Trump isn’t just violating the law. He is also undermining the credibility and moral authority of the United States.

In keeping with his transactional view of foreign policy, Trump seems all too willing to sell out America’s principles. But what has his approach added to the other side of the ledger? He claims that the value of Saudi arms deals, as well as Saudi Arabia’s assistance in meeting our strategic goals in the region, require us to mute our objections to the regime’s offenses. But those purported billions of dollars in weapons sales and advances in Middle East peace have yet to materialize.

There is no artistry to the deal if you are willing to cave on the key terms. For decades, presidents of both parties have steadfastly avoided this easy route, taking difficult stands to show the world that the United States will never compromise its convictions.

This is why, six months later, Jamal Khashoggi’s story is not fading. Instead, each day that justice goes undone, the consequences of his murder grow more troubling. Each day that Trump allows the Saudis to avoid accountability, the more tyrants around the world come to believe that they, too, can kill with impunity. Each day, the reputational value that past generations of Americans have built up is squandered.

As Trump once observed, “The world is a very dangerous place.” This is why the United States must always stand tall and never surrender its values. Congress must continue to do everything in its power to hold Khashoggi’s killers responsible. Administration officials should look at shocking evidence that reinforces the conclusions of our intelligence agencies. And Trump must, at minimum, obey the law — and produce the findings that the Magnitsky Act requires.

Another six months cannot pass without accountability for this abhorrent crime. Justice for an innocent journalist — and America’s most crucial interests — require nothing less.