In 2003 the CIA captured a Pakistani named Majid Khan, took him to an overseas black site, and began to torture him. According to Khan, interrogators beat him, waterboarded him, and hung him from a beam naked for days. He spent most of one year in the dark. They threw ice water on him, deprived him of sleep, and subjected him to “violent enemas.” Even his memories of the abuse were not his own; the CIA has considered recollections of interrogation to be classified information, thus forbidding detainees from speaking or writing publicly about their experiences. Notes taken by Khan’s lawyers were finally cleared for release in May, and were reported by Reuters last week.

The grisly new details of Khan’s treatment indicate that we are still far from a public accounting of the full extent of the CIA’s interrogation tactics, much less accountability for the officials involved. But there is new movement in the Senate to reinforce the prohibition on torture, so that the CIA cannot do to others what it did to Khan.

On Tuesday, Senators John McCain and Dianne Feinstein introduced an amendment to the National Defense Authorization Act designed to eliminate the CIA’s ability to interpret its way around the torture bans already on the books. If passed, the amendment, which has broad support from human rights groups, would be the first concrete action following up on the partial release of the Senate’s torture report last year. It codifies President Obama’s 2009 executive order rolling back the Bush administration’s interrogation policies—an order that could be rescinded by a future administration, which at least one Republican presidential candidate has indicated he would do.

The measure restricts the government’s use of interrogation tactics to those that are specifically permitted by the Army Field Manual, a public document that currently prohibits many of the Bush-era tactics. In theory this would eliminate gray area so that a future administration cannot secretly approve the sort of methods used on Khan—methods that any reasonable person would conclude conflict with broad bans against inhumane treatment contained in the Geneva Conventions, the Convention Against Torture, and the Detainee Treatment Act.

Still, the Army manual doesn’t eliminate all potential for abuse. A section called Appendix M has been criticized by the UN Committee against Torture and others for authorizing some techniques, including sensory and sleep deprivation, that could be used inhumanely. The McCain/Feinstein amendment does require the manual to be reviewed and publicly updated every three years to ensure it “complies with the legal obligations of the United States” and that its approved practices “elicit reliable and voluntary statements that do not involve the use or threat or force.” If it passes, human rights groups will undoubtedly press for revisions to that appendix.

The McCain/Feinstein proposal also requires the government to give the International Committee of the Red Cross “notification of, and prompt” access to detainees. This is intended to prevent interrogators from holding prisoners in undisclosed overseas detention facilities. Again, this protection is not without gaps: the amendment doesn’t ban black sites outright.

In addition to human rights advocates, a number of intelligence and defense experts are pushing Congress to approve the measure. One of them is Torin Nelson, a former Army interrogator with experience in Afghanistan, Iraq, Bosnia, and Guantánamo Bay. “I’m not some sort of bleeding-heart liberal guy who wouldn’t use it if it worked,” Nelson said Wednesday during a break from speaking with senators about the amendment. “We need to change the narrative of people who are advocating for torture or torture-light by using terms such as ‘enhanced’ interrogation techniques. That is a piss-poor way of describing those techniques …. The techniques they are talking about are amateurish.”

Laws passed by Congress are only as good as their enforcement. The most critical thing the McCain/Feinstein amendment can’t do is ensure that officials who violate the law are held accountable. Instead, by refusing to prosecute or even investigate those involved with the CIA’s torture program, including CIA director John Brennan, the Obama administration has sent a signal that others will get off scot-free. “Requiring the CIA and other US agencies to abide by one uniform set of interrogation rules will help prevent torture,” said Laura Pitter, senior national security counsel for Human Rights Watch, in a statement. “But such legal fixes won’t carry weight in the future if those responsible for torture in the past aren’t brought to justice.”