Newly declassified papers on the U.S. government's role in Argentina's 1976-83 "Dirty War" have been released, detailing—among other things—how former secretary of state Henry Kissinger stymied attempts to end mass killings of dissidents.

The files were published just after Politico reported that Democratic presidential nominee Hillary Clinton is courting Kissinger's support, among other Republican elites.

Kissinger lauded Argentina's military dictatorship for its "campaign against terrorism," which included the imprisonment, torture, and killings of tens of thousands of leftist activists and students, the files reveal.

"His praise for the Argentine government in its campaign against terrorism was the music the Argentine government was longing to hear," one document states.

During a private meeting with the conservative diplomat group Argentinian Council of International Relations (CARI), Kissinger said that "in his opinion the government of Argentina had done an outstanding job in wiping out terrorist forces."

U.S. ambassador to Buenos Aires, Raúl Castro warned that Kissinger's praise for the military dictatorship "may have gone to some considerable extent to his hosts' heads."

"There is some danger that Argentines may use Kissinger's laudatory statements as justification for hardening their human rights stance," Castro said.

Clinton herself has come under considerable scrutiny for her role in other U.S.-backed coups in Latin America, such as Honduras.

Further, during a presidential debate with then-rival Sen. Bernie Sanders (I-Vt.) in February, Clinton cited Kissinger as someone she looks to for advice and approval on foreign policy; Sanders called that reference "rather amazing," stating, "I happen to believe that Henry Kissinger was one of the most destructive secretaries of state in the modern history of this country. I am proud to say that Henry Kissinger is not my friend. I will not take advice from Kissinger."

On Tuesday, following Politico's report, progressives called on Sanders and his surrogates to withdraw their support of Clinton if she allies with Kissinger.

As Greg Grandin writes at The Nation:

If Sanders stands for anything, it is the promise of decency and civil equality, qualities that he has worked hard to bestow on Clinton since the Democratic National Convention. By accepting Kissinger's endorsement, Clinton wouldn't just be mocking that gift. She'd be sending the clearest signal yet to grassroots peace and social-justice Democrats that her presidency wouldn't be a "popular front" against Trumpian fascism. It would be bloody business as usual.

Elsewhere in the documents—released on President Barack Obama's order in a gesture of goodwill toward Argentina—U.S. diplomats and officials can be seen wondering whether their foreign policies had gotten out of control.

The National Security Council's Latin America director, Robert Pastor, wrote in a dispatch to then-President Jimmy Carter's national security adviser Zbigniew Brzezinski, "Have we gone too far? Have we pushed our policy beyond its effectiveness? Are we pushing the Argentines over the edge and jeopardizing our future relationship? Does the terror justify the repression?"

"I, myself, believe that we may have...pushed too far," Pastor wrote.