If the CIA Illegally spied on the U.S. Senate, we might never know, thanks to inertia.

The Department of Justice will not investigate whether the Central Intelligence Agency illegally spied on staffers of the Senate Intelligence Committee and removed documents from committee servers, McClatchy News Service confirmed Thursday. The CIA also claimed committee staffers took documents from the intelligence agency without authorization. That claim also won’t be investigated.

“The department reviewed the matters referred to us and did not find sufficient evidence to warrant a criminal investigation,” Justice Department spokesman Peter Carr told McClatchy.

It’s a fizzling denouement to one of the more fascinating political dramas of the Obama era. Earlier this year, without any warning, Intelligence Committee Chair Dianne Feinstein, D-California, took the Senate floor and delivered a forceful speech accusing the CIA of spying on committee computers and removing documents.

The backstory is that the Intelligence Committee conducted an extensive investigation into Bush-era torture, and produced a 6,300-page report that is not yet public. It is reportedly a “searing” indictment of the agency – and the CIA responded by denying many of the damning charges.

INVESTIGATORS CAME ACROSS WHAT’S KNOWN AS THE “PANETTA REVIEW,” ORDERED BY LEON PANETTA.

The problem is that investigators came across what’s known as the “Panetta review,” an internal review ordered by former CIA director Leon Panetta that reportedly confirms most of the worst findings about torture by CIA agents. It’s this review that Feinstein publicly charged the CIA with removing from private committee computers after gaining illegal access.

This is a serious charge – it’s not substantially any different from CIA agents breaking into a physical Senate office and removing files.

What’s odd about Justice’s refusal to pursue a formal investigation is that Feinstein claims CIA Director John Brennan essentially admitted the cyber break-in. In March, she said, Brennan requested an emergency meeting to inform her that without prior notification or approval, CIA personnel had conducted a ‘search’ – Brennan’s word – of the committee computers at the offsite facility.

According to Brennan, the computer search was conducted in response to indications that some members of the committee staff might already have had access to the Panetta review.

Feinstein said she is at least happy the DOJ won’t investigate the CIA’s claim that committee staffers stole the Panetta report from CIA computers.

A second-party retelling of a confession may not be enough to obtain a conviction, but it’s hard to imagine there is not enough smoke here to at least pursue an investigation. Aside from the immediate implications regarding Bush-era torture – and, with the revelations this week about CIA spying in Germany, an agency that may essentially be going rogue – the incident raises grave concerns about constitutional separation of powers.

GEORGE ZORNICK writes regularly for The Nation.