"We tortured some folks,” President Barack Obama said in 2014. Indeed. And now, from the December 9 Senate Intelligence Committee report, we know more about how it was done. Prolonged isolation and sleep deprivation. The beatings and painful shackling. The forced rectal intrusions. The waterboarding. We also now know about the hallucinations, suicide attempts, and heavy bruising. And we know, finally, that American interrogators often committed these abuses against innocent people: Whatever lack of sympathy some observers might have for detainees of the CIA, the summary reveals that many were not involved in criminal activity at all. One in five didn’t even meet the CIA’s own criteria for detention. Many of the 119 CIA detainees eventually were released.

Legally, the U.S. government now is obliged to act against the torturers under international law. As a party to the U.N. Convention against Torture, the United States is not only obligated to criminalize torture—which it did when it passed the U.S. Torture Statute in 1994—but also to investigate and prosecute cases of torture under its jurisdiction. The U.S. government, under the Obama administration, has not met this obligation. President Obama, a constitutional lawyer, has failed to observe the law—to ensure that those responsible for planning and carrying out a program of torture have been prosecuted.

The CIA and its defenders suggest that the tactics used were justified by the CIA’s reliance on legal opinions issued by the Justice Department’s Office of Legal Counsel, so prosecutions are unwarranted, and would fail if they occurred: CIA officers can invoke a defense of “good faith reliance on counsel.”

This argument is wrong, and also partially misses the point.

The truth is that the conduct described in the report was torture—there is no doubt about it—and it simply is not true that the CIA thought otherwise, or was relying in good faith on legal advice.

The fact is, senior officials knew the conduct was illegal. One of the most significant documents revealed in the Senate report is a letter distributed internally within the CIA in mid-2002 in which CIA lawyers acknowledged that the program’s techniques violate the U.S. torture statute. The document—which was shared even with interrogators—shows that senior CIA officials and personnel involved in interrogations actually knew from the start of the program that they were torturing suspects and were looking for legal cover.

A previous Justice Department internal investigation contains accounts from White House and Justice officials showing that lawyers from the CIA and the Office of Legal Counsel, in 2002, essentially conspired to legalize the illegal. They first sought advance immunity from the Justice Department’s Criminal Division, and when that failed, worked with the department’s Office of Legal Counsel to draft the now infamous “torture memos.” Since the CIA and its interrogators already knew the tactics were torture, they cannot invoke the defense, nor for that matter can the attorneys and White House officials who worked on the memos—on the contrary, the revelations in the report suggest that their actions too were criminal: they appear to have engaged in a conspiracy to commit torture, by facilitating the CIA’s interrogation program and then using their offices to evade the law.

And whoever said torture was the only issue? The tactics outlined in the Senate summary include violations of other criminal statutes: assault, aggravated assault, sexual abuse, homicide, and war crimes. And that’s not even getting into the realm of conspiracy laws, and crimes for lying to Congress. There is plenty of grist for the prosecutorial mill, and no reason why the case can’t get stronger as prosecutors work their way through the perpetrators, reaching plea deals with some of them to strengthen cases against other more central characters.

The president has said that he wants to be “looking forward, not back.” Yet this idea, reflexively attractive as it may sound to some, is a grave insult to the concept of justice, which by definition involves looking at events in the past and holding wrongdoers accountable. In any case, the future is written by the past. If Obama doesn’t act, he allows a precedent to stand: future presidents will draw the lesson that torture can be committed as part of a widespread government program in response to a national security event. Torture will remain on the table as a potential policy option.

Accountability is the key issue now, the missing element in how Obama has addressed the torture conducted under his predecessor’s administration.

CIA Director John Brennan himself unwittingly made this point in his December 11 news conference, when he acknowledged that it is “unknowable” whether information obtained by the CIA’s torture could have been obtained by other means. Even in the face of a devastating Senate summary, Brennan said he would be unable to give assurances that the CIA might not utilize its past tactics again in the face of future incidents similar in gravity to the September 11 attacks. “I defer to the policymakers in future times,” he said. In short, the CIA could be open to torturing again someday.

To ensure that doesn’t happen, someone must pay.

John Sifton is an Advocacy Director at Human Rights Watch and formerly the organization’s Senior Researcher on Terrorism and Counter-terrorism. Follow him on Twitter at @johnsifton.