WASHINGTON — Two members of the Senate Intelligence Committee on Wednesday announced their support for declassifying parts of a long-delayed report on the C.I.A.’s defunct detention and interrogation program, all but assuring that the committee will approve the report and send it to President Obama for eventual release.

The announcement by Maine’s two senators — Susan Collins, a Republican, and Angus King, an independent — effectively ended any suspense about whether the committee’s chairwoman, Dianne Feinstein, Democrat of California, will have enough votes to declassify the voluminous report’s conclusions and executive summary, which are said to make up about 400 pages of the 6,300-page report. The committee’s other Republicans oppose the conclusions of the report, but support from Ms. Collins and Mr. King for releasing the report will give a veneer of bipartisanship to the committee’s vote.

The vote on the report, scheduled for Thursday afternoon, will bring at least partial closure to the years of partisan jousting on the committee about the report, which sets out to tell the history of what is perhaps the most controversial response by the administration of George W. Bush to the terrorist attacks of Sept. 11, 2001.