On October 2, Jamal Khashoggi walked into the Saudi Arabian consulate in Istanbul. He was brutally murdered, likely dismembered, and his remains surreptitiously disposed of. His killers were almost certainly dispatched from Riyadh by high-ranking members of the government of Saudi Arabia, an absolute monarchy run by Mohammed bin Salman, the country’s crown prince and a close American ally. If Turkish claims are to be believed—and under its present leadership that is a serious caveat—some of those Saudi henchmen have direct ties to the crown prince. According to reports, one of them, an autopsy specialist, entered the country with a bone saw.

Khashoggi, a Saudi dissident who obtained U.S. residency in 2017, lived in Virginia and wrote for the Washington Post. Turkish authorities say they have audio recordings of him being dismembered, though they appear to be holding on to them as part of a calculated series of leaks. The New York Times cites “American officials” claiming awareness of intelligence intercepts of Saudi operatives discussing the possibility of detaining Khashoggi.

Donald Trump, as is his custom, chose early on to speak about the affair in the absence of facts or knowledge. At first he repeated King Salman’s claim of puzzled innocence, then Trump suggested “rogue killers” inside the consulate may have been responsible. The president sent Secretary of State Mike Pompeo to meet with the king and the crown prince, but this resulted only in more happy talk, and the administration’s insistence that Saudi authorities be given time to conduct a thorough and “transparent” investigation.

The likelihood is that the regime of Mohammed bin Salman, MBS as he’s known, will claim that Khashoggi’s death resulted from an unauthorized operation gone awry, that a new senior intelligence official was too eager to prove himself. Few will believe this, but the question arises: What can the United States do about it? After all, a chorus of Western powers hit Vladimir Putin’s regime with sanctions after the attempted murder of former spy Sergei Skripal to little avail.

There is also a crucial difference between Russia and Saudi Arabia: One is an implacable foe that undermines U.S. interests at every opportunity; the other is a valuable ally in a region that has long been dominated by anti-Americanism. One need not deny that Saudi Arabia routinely violates the civil rights of its citizens and the human rights of its critics, or that it has often been complicit in funding Islamic extremism around the world, to acknowledge the importance of the U.S.-Saudi relationship and the potential folly of alienating the kingdom at a time when Iranian imperialism threatens the entire Middle East.

Iran, of course, lurks in the background of any debate over Saudi Arabia. Predictably, former members of the Obama administration and their cheerleaders in the foreign-policy world would like the current administration to overreact to the Khashoggi tragedy by sanctioning Saudi Arabia and meting out various other diplomatic punishments. This is a crime that deserves consequences, but the counsel to isolate the kingdom springs from more than concern over an unpardonable act in Istanbul. The Obama administration threw its lot in with Iran, Saudi Arabia’s great enemy, in the hope that normalizing relations with Tehran and lifting sanctions would allow the lawless, terrorist-abetting regime to join the community of civilized nations. It didn’t work. The mullahs duped the United States—in no small measure because the Obama administration wished to be duped. To this day, Iran funds terror networks across the Middle East, colludes with malign regimes from Moscow to Pyongyang, and almost certainly pursues its supposedly forsworn aim of acquiring nuclear weapons.

It’s a bit rich, therefore, for the champions of U.S.-Iranian rapprochement to demand that the United States isolate Riyadh over one admittedly shocking crime. Even if we conclude that MBS is largely responsible for this horrific killing (and an ugly war in Yemen), the Saudis’ value to the West stands in stark contrast to the menacing terror regime known as the Islamic Republic of Iran. That’s even truer in light of the fact that, for all his and his government’s brutality in important regards, MBS is cautiously leading Saudi Arabia toward closer relations with Israel—and behind the scenes he is pushing for this relationship forcefully. His domestic reforms are real, too. They may prove illusory, but it’s unclear why the United States should demand, as some are suggesting, that MBS relinquish his office. Perhaps this is a just course after the horror in Istanbul, but it would have consequences, too. MBS’s replacement might refrain from extrajudicial killings but he is also sure to have far less interest in domestic reform and leaving behind Saudi Arabia’s long history of support for extremism.

The Trump administration would be ill-advised, however, to sidestep the scandal. The facts point more and more decisively to Saudi guilt. Weeks before the Khashoggi affair, key House Republicans were already signaling their unhappiness with U.S. aid to Saudi Arabia’s war in Yemen, and Congress may yet wish cut off those funds as a warning to MBS. What’s most vitally important is that the administration not make itself complicit in a Saudi cover-up, that it insist on the frankest admission that an absolutist state can make. We hope the secretary of state will call murder what it is, and insist that the president do the same.