The Central Intelligence Agency has been spying on members and staff of the US Senate committee charged with oversight of intelligence activities, according to statements issued by several senators and confirmed by multiple sources in press reports Wednesday and Thursday.

Exposure of the spying has triggered first an investigation by the CIA inspector general, David Buckley, and then a criminal referral to the Department of Justice. There is a potential for criminal prosecution of CIA officials, both those who engaged in the illegal spying and those who authorized it.

What is involved is a major violation of the constitutional separation of powers between the executive branch, of which the intelligence apparatus is part, and the legislative branch. At least one Senate Democrat, Mark Udall of Colorado, has suggested that President Obama was aware of the spying, potentially an impeachable offense.

The CIA spying on Congress arises out of the protracted investigation by the Senate Intelligence Committee into the use of torture in secret CIA prisons set up in Europe and Asia in the period after the 9/11 terrorist attacks.

The Senate panel compiled a 6,300-page report that documents widespread violations of international law and the Geneva Conventions, which bar torture, indefinite imprisonment, kidnappings (rendition) and other measures employed by the US intelligence apparatus in the name of the “war on terror.” It also documents systematic lying by CIA officials to Congress.

The CIA has stalled publication of the report, which remains classified, with the support of the Obama White House, which has consistently opposed any exposure of the torture program or punishment of those involved. Obama rejected calls to prosecute Bush administration officials for their role in the torture program, and the Justice Department dropped all charges against lower-ranking CIA agents in 2012.

Last September, CIA Director John Brennan filed a 122-page rebuttal of the Intelligence Committee report, which also remains secret. Some time later, Senate committee staffers working at a secure facility at CIA headquarters reportedly discovered an internal CIA document—a review of the torture program commissioned by Brennan’s predecessor, Leon Panetta—which conceded that the main claims of the Intelligence Committee report were justified. The CIA withheld this document from the Intelligence Committee in an effort to bolster Brennan’s hard-line position.

Senator Mark Udall, a member of the Intelligence Committee, revealed the existence of the Panetta report in December, saying that it was “consistent with the Intelligence Committee’s report” and “conflicts with the official CIA response to the committee’s report.”

This revelation in turn triggered a CIA investigation into how the committee had learned of the Panetta report, which included monitoring the computers used by Senate staffers as they conducted oversight work in a room set aside for their exclusive use at CIA headquarters in Langley, Virginia. A declaration filed by Neal Higgins, the CIA’s director of congressional affairs, states that all materials used by the Senate staffers working at the CIA building “are the property of the committee” and “remain congressional records in their entirety.”

According to a report by McClatchy News Service, which has conducted the bulk of the original reporting on this issue, “The committee determined earlier this year that the CIA monitored computers – in possible violation of an agreement against doing so – that the agency had provided to intelligence committee staff in a secure room at CIA headquarters that the agency insisted they use to review millions of pages of top-secret reports, cables and other documents, according to people with knowledge.”

The first hint of the illegal CIA monitoring came when another Intelligence Committee member, Senator Ron Wyden of Oregon, asked CIA Director Brennan at a January 9 hearing if provisions of the Federal Computer Fraud and Abuse Act “apply to the CIA.” Brennan deferred an answer, later sending a letter to Wyden conceding that law did apply to the CIA, but claiming the law does not prohibit any “lawfully authorized investigative, protective or intelligence activity” carried out by the spy agency.

It was apparently the CIA’s own investigation into the leaking of the Panetta report—which generated charges that Senate staffers had engaged in “unauthorized” entry into the CIA computer system and removed documents from CIA headquarters—that tipped off the Senate panel and its staff that their computers were being monitored.

The press reports suggest three levels of criminality on the part of the CIA: the torture program itself, whose authors include President Bush, Vice President Cheney, and other top officials of the Bush administration; the suppression of the Panetta report, a cover-up carried out under Brennan and the Obama administration; and the illegal spying on Senate staffers, also carried out under Brennan and Obama.

The response of the corporate-controlled American media has been, for the most part, to ignore the affair and obscure its significance. This is not because, as the New York Times coverage suggests, the details are complicated and the issues murky. On the contrary, while the maneuvers of the CIA in this matter are complex, the illegal and unconstitutional character of the agency’s actions is evident and obvious.

Senate Democrats have done their best to muddy the waters as well. This applies both to the open and unabashed defenders of every crime by the intelligence apparatus, like Senator Dianne Feinstein, chair of the Senate Intelligence Committee, and the “critics” on the panel, like Udall and Wyden.

Udall sent a cryptic letter to President Obama Tuesday, which made only the vaguest reference to the illegal spying. He wrote, “As you are aware, the C.I.A. has recently taken unprecedented action against the committee in relation to the internal CIA review, and I find these actions to be incredibly troubling for the committee’s oversight responsibilities and for our democracy.”

Given that this was the first official communication from Congress to the White House on the CIA spying on the Senate, Udall’s “as you are aware” suggests knowledge that Obama was previously informed about the surveillance by the CIA itself. This would make the White House directly complicit in the constitutional violation.

CIA Director Brennan has remained adamant in defending the agency and suggesting that it was the Senate staffers, not the intelligence operatives, who had engaged in illegal actions. “I am deeply dismayed that some members of the Senate have decided to make spurious allegations about CIA actions that are wholly unsupported by the facts,” he said in a statement issued Wednesday. “I am very confident that the appropriate authorities reviewing this matter will determine where wrongdoing, if any, occurred in either the Executive Branch or Legislative Branch.”

In response to the initial press reports of CIA spying, Republican Senator John McCain of Arizona said, “We just can’t have that happen in a democracy. There’s separation of powers between the legislative branch and the executive branch. It’s very disturbing.” Senate Armed Services Committee Chairman Carl Levin, a Democrat, called the charges “extremely serious. There are laws against intruding and tampering, hacking into, accessing computers without permission. And that law applies to everybody.”

But Senate Majority Leader Harry Reid downplayed the issue, saying he would be guided by Feinstein. “I’m going to wait and see what direction she takes,” he said, adding, “this is an issue I await for the inspector general’s report.”

As Reid’s comments indicate, there is not the slightest prospect of a serious investigation into the CIA spying on Congress from the Democrats or the Obama administration.

These revelations pose the question: If this is what the CIA does to its congressional watchdogs (in reality lapdogs), what is it doing to those it actually targets as enemies, both abroad and especially at home? That is a question that only can be answered through independent political action by the working class, and all those genuinely concerned with the defense of democratic rights.