Loujain al-Hathloul is shown in a 2014 video image. She is one of the arrested activists who pushed for the right of women to drive in Saudi Arabia. (Loujain Al-Hathloul/AP)

PRESIDENT TRUMP and his top aides continue to doggedly defend Saudi Arabia’s Crown Prince Mohammed bin Salman despite what members of Congress briefed by the CIA say is compelling evidence he was behind the murder of journalist Jamal Khashoggi. On Tuesday, Mr. Trump, who once promised “severe punishment” for those responsible for the killing, responded to a question about the crown prince’s complicity by saying: “He’s the leader of Saudi Arabia. They’ve been a very good ally.” The next day Secretary of State Mike Pompeo, asked about consequences, said, “The Saudis have already paid the price.”

In fact, there has been no significant cost for Mohammed bin Salman and his regime. Members of the hit team that traveled to Istanbul to murder Mr. Khashoggi are said to have been arrested, but nothing is known about charges, trials or possible punishment; not even their names have been released. The Trump administration says it has imposed sanctions on 17 people, but travel bans and asset freezes are meaningless for most of them — and the administration left off its list the senior intelligence official who the Saudis admitted was implicated in the plot. The Senate was debating resolutions Wednesday to cut off funding for Saudi military operations in Yemen or to condemn Mohammed bin Salman, but neither is likely to be approved by the House.

This impunity is not only a moral failing; it is also a missed opportunity. Even if they judge it necessary to maintain close relations with Mohammed bin Salman — a dubious proposition — Mr. Trump and his advisers ought to be demanding tangible concessions in exchange. These should not concern arms purchases or the price of oil — the latter of which the Saudis last week moved to raise in contravention of Mr. Trump’s demands. They should center on free expression and human rights, which is what the Khashoggi case is about.

One matter in particular cries out for U.S. attention: the Saudi women jailed and reportedly tortured for advocating civil rights, including permission to drive. The regime allowed women to drive earlier this year, but then arrested the activists who had peacefully advocated for reform. One of the most prominent, Loujain al-Hathloul, was abducted on a highway in the United Arab Emirates in March and forcibly returned to Saudi Arabia. She was released after a few days but then disappeared again in May along with a number of other women; other arrests followed in August. Eleven women remain in custody, according to Reuters.

Several women arrested in May were held incommunicado and in solitary confinement for three months, Amnesty International reported, and they remain detained without charge or legal representation. More disturbingly, The Post, Amnesty and Reuters have separately reported that several of the women have been subjected to torture and sexual abuse. According to accounts provided to The Post by four people, the women were beaten or subjected to electric shocks, and when visited had difficulty standing. The Reuters account says a top aide to Mohammed bin Salman, Saud al-Qahtani, was present when one of the women was subjected to forced kissing, groping and electric shock, and threatened her with rape and murder.

The Trump administration seemingly cannot bring itself to seek justice for Mr. Khashoggi. But it could, at least, intervene on behalf of the living and demand that Mohammed bin Salman release the female activists. If the crown prince cannot meet this simple test, surely he cannot be rehabilitated as a reliable U.S. partner.