America’s values are being tested today.

The Senate is expected to vote at 11:30 a.m. on an amendment “to reaffirm the prohibition on torture.” Sponsored by Senators Dianne Feinstein, Jack Reed, Susan Collins, Jeff Flake, and John McCain, who was tortured by Communist forces in Vietnam, Amendment 1889 is intended as a rebuke to the CIA, which broke the civilizational taboo against inflicting physical and mental anguish on prisoners.

And it is meant to prevent future presidents from violating binding international treaties, United States law, and basic morality, as would reoccur if they followed the barbaric precedents of George W. Bush, Dick Cheney, John Yoo, Jay Bybee, and others whose legacies include water torture, rectal feeding, and death by hypothermia.

President Obama entered office having campaigned against torture and issued an executive order prohibiting it in 2009. But that order could be reversed on the whim of the next person to control the executive branch and its too-pliable lawyers.

In contrast, if the amendment passes the Senate, gets Obama’s signature, and makes its way into federal law, all federal agencies would be required to conduct interrogations in accordance with the Army Field Manual. And transparency provisions would prevent that manual from being changed under cover of secrecy. Put simply, the amendment would erect more obstacles to torture than Bush and Cheney faced on the theory that those obstacles proved totally insufficient.

Perhaps the amendment would be unnecessary if Obama would’ve pursued criminal charges against the architects of the torture program, as an international treaty signed by Ronald Reagan and ratified by the U.S. Senate required him to do.

Had the Senate intelligence committee released its entire torture report rather than just an executive summary, the CIA might be less likely to torture again in the future.

But elected officials chose to let the torturers off and to understate their misdeeds. "In the immediate aftermath of 9/11 we did some things that were wrong," Obama once said. "I understand why it happened. I think it’s important when we look back to recall how afraid people were after the Twin Towers fell and the Pentagon had been hit and the plane in Pennsylvania had fallen, and people did not know whether more attacks were imminent, and there was enormous pressure on our law enforcement and our national-security teams to try to deal with this."

But as I noted at the time, the Bush administration did not just torture a few al-Qaeda members on September 12, 2001, to see if any more attacks were imminent. It didn’t stop embracing torture “in the immediate aftermath of 9/11” or even by the end of 2002 or 2003. On May 10, 2005, "Steven Bradbury of the OLC authored a detailed, 46-page memo to John Rizzo, the CIA counsel, authorizing a variety of coercive interrogation techniques and arguing that even the harshest techniques are not torture,"Annie Lowrey noted in her helpful timeline on Bush-era torture. In 2006, she added, Dick Cheney "said waterboarding's a no-brainer" in an interview. Even in 2007, George W. Bush "thwarted congressional efforts to restrict CIA interrogation techniques to those authorized for the military and signed an executive order allowing the CIA to use harsher methods."

Mitt Romney’s advisers urged him to rescind Obama’s executive order ending torture if he was elected in 2012. The 2016 GOP nominee may well be a torture proponent. For these reasons and more, the Senate amendment is needed. It is long past time for Congress to tell the executive branch that it shall not torture in America’s name.