"At that time, I thought [Kavanaugh] had the qualifications for the Supreme Court should he be selected", Stevens said. Heidi Heitkamp, N.D., and Joe Manchin III, W.Va., also have yet to announce how they will vote.
Kavanaugh has not yet locked up the votes needed.
The Senate, in which the Republican have a narrow 51-49 majority, is due to vote on Kavanaugh's confirmation on Saturday.
Kavanaugh promised in the piece, titled "I am an independent, impartial judge", that his tone was not an indication that his open-mindedness would change if the Senate confirms him to the nation's highest court. Republicans did not want to pursue whether Kavanaugh lied to the Senate Judiciary Committee about his alcohol use in high school and college.
Crowds of activists, many of whom wearing black - commonly associated with supporting sexual assault survivors - swarmed inside the Hart Senate Office Building Thursday afternoon. Democrats started mobilizing after the shell shock of Trump's election wore off. Look at the Women's Marches of 2017 and 2018.
Polls are showing that this nomination fight has animated Republicans like no other.
A procedural vote on Kavanaugh's nomination is scheduled for 10:30 a.m. EDT Friday.
At the MS rally, Trump also turned his ire on Julie Swetnick, who claims Kavanaugh took part in efforts at parties during high school to get girls intoxicated so that groups of boys could have sex with them.
Melania Trump looks happier hanging out with African children than Donald Trump
Trump joins a list of former first ladies - Hillary Clinton, Laura Bush and Michelle Obama - who also made solo trips to Africa. Trump plans to visit a hospital neonatal intensive care unit before going to the presidential palace for tea with Akufo-Addo.
Mr Flake and Ms Collins are joined by a third undecided Republican, Lisa Murkowski, of Alaska. She paid two visits to the off-limits room where the document was being displayed to lawmakers. Even she backpedaled on some of the details during her interview with NBC.
Christine Blasey Ford said he drunkenly groped her and attempted to take her clothes off in what she believed was a rape attempt when they were teenagers decades ago.
A hefty police presence added an air of anxiety, as did thousands of anti-Kavanaugh demonstrators.
Capitol Police said the 300-odd detainees were processed on site and released after being charged with offenses such as obstructing a public space or unlawful demonstration. The agency has also spoken to a second woman, Deborah Ramirez, who has claimed Kavanaugh exposed himself to her at a Yale party when both were freshmen.
They asked the president to "adhere to precedent and direct the Federal Bureau of Investigation to immediately and thoroughly investigate [allegations against Kavanaugh] and provide a report to the Senate as soon as possible".
Senators said the documents they examined totaled about 50 pages.
Prof Blasey Ford testified last week at a dramatic Judiciary Committee hearing that when she was 15, a drunken 17-year-old Kavanaugh pinned her down, tried to remove her clothing and covered her mouth after she screamed.
Countered Maine's Republican Sen. Thom Tillis, including screenshots that "were very helpful" in understanding the communications between various people discussing the situation.
Connecticut Democrat Chris Murphy said on Twitter that with each senator being given one hour to review the report before a "rushed vote", the confirmation process controlled by Republicans is "just about power politics".