The Senate Intelligence Committee is poised to vote in favor of declassifying a report on the CIA's controversial interrogation and detention program Thursday, putting in motion the process of making public a report that has been years in the making.

Though the 6,300-page report is not public, early leaks about its contents suggest it will not paint the CIA in a flattering light. The Washington Post reported earlier this week that it says the agency covered up the extent of the brutality of its programs, exaggerated the importance of certain prisoners and wrongly suggested that its interrogation methods were responsible for getting key pieces of information.

Despite longstanding Republican opposition to the report, the effort to declassify got bipartisan support Wednesday when the two senators from Maine, Republican Susan Collins and independent Angus King, announced they would vote in favor of the report because "its findings lead us to conclude that some detainees were subjected to techniques that constituted torture."

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"Our vote to declassify this report does not signal our full endorsement of all of its conclusions or its methodology," the pair said in a joint statement, citing the fact that it did not involve direct invterviews with CIA officials, contract personnel, or other executive branch personnel.

"We do, however, believe in transparency and believe that the Executive Summary, and Additional and Dissenting Views, and the CIA's rebuttal should be made public with appropriate redactions so the American public can reach their own conclusions about the conduct of this program," the statement said.

The report is largely the work of Democratic staff. The ranking Republican on the committee, Georgia Sen. Saxby Chambliss, said when the report was approved in 2012 that, "a number of significant errors, omissions, assumptions, and ambiguities--as well as a lot of cherry-picking--were found that call the conclusions into question," partially because it was written without conducting interviews with people involved. The vote was 9 to 6 in favor of approving the report, with only Sen. Olympia Snowe, R-Maine, joining Democrats.

Still, Chambliss told the New York Times in 2013 that he believed a summary of the report could be made public as long as included a summary of the CIA's response and a dissent from the committee's Republicans.

The panel's chairwoman, Sen. Dianne Feinstein, D-Calif., has defended it as "one of the most significant oversight efforts in the history of the United States Senate, and by far the most important oversight activity ever conducted by this committee."

Even with the expected vote in favor of declassifying Thursday, it could still be weeks or even months before executive summary, findings and conclusions are made public. The request would first go through the White House, where President Obama has spoken in favor of releasing the report.

"This is a question about the credibility of the CIA and what they said about the effectiveness of this program," said CBS News National Security Analyst Juan Zarate. "What we're going to see is out in the open further debate about the enhanced interrogation techniques that were applied by the CIA in the first and early parts of the Bush administration."

The vote comes in the midst of a larger fight between the Intelligence Committee and the CIA, with each accusing each other of potentially criminal activity.

Feinstein charged that the CIA had spied on the committee's staff while the staff was working on the report. CIA Director John Brennan said was "beyond the scope of reason" to allege that the CIA "hacked" the Senate Intelligence Committee. The CIA, meanwhile, filed a crimes report with the Justice Department against the Intelligence Committee, suggesting committee staffers weren't authorized to access all the documents they obtained.