The Washington Post report details the stories of four women who described that Moore expressed interested in them sexually when they were teens.
Gardner, who's heading the national Republicans' Senate campaign arm this cycle, endorsed Moore in September after he won the primary - a pitched battle between establishment Republicans backing unusual and Moore supporters, including former top Trump strategist Steve Bannon - saying the NRSC has always been focused on "keeping a strong Republican majority in the Senate, and that includes Alabama".
The report immediately led to sweeping backlash in the political world, with a number of prominent members of Moore's own party calling for the candidate to withdraw from the race if the story is genuine.
On Thursday, senior Republicans swiftly called for Moore to step aside from the Senate race if the allegations are shown to be true. Luther Strange in a primary and faces Democrat Doug Jones in December race to fill attorney general Jeff Sessions seat.
On a second visit, he took off her shirt and trousers, stripped to his underwear, touched her over her bra and underpants, and guided her hand to touch his crotch, she told the Post.
Of course, Moore has defined himself as being opposed to everything that McConnell and the national Republican establishment stands for, and, at least at first, judging from his campaign's reply to the story, Moore seems to be determined to brazen things out on familiar lines. 'I remember talking to her and telling her it's not a good idea, ' said Betsy Davis, who remembers her friend seeing an older man named Roy Moore.
Corfman, then 14, told the newspaper that Moore picked her up around the corner from her home and took her to his place where he told her she was pretty and began kissing her. He offers to watch over the girl while her mother goes into a child custody hearing.
Texas Sen. John Cornyn said, "If it is true I don't think his candidacy is sustainable".
"I wanted it over with - I wanted out", she told the newspaper.
The top Senate Republican said Mr Moore must step aside if the claims are true.
His campaign later added that the allegations were "garbage" and the "definition of fake news".
On Thursday, the Washington Post reported that politician and Alabama state judge Roy Moore allegedly initiated contact with several teenagers girls in the late 1970s and early 1980s. Moore defeated Luther Strange, the Republican who had been appointed to the seat, in a September primary.
Moore became a national figure in the early 2000s, when he lost his position as Alabama Chief Justice after refusing a court order to remove a Ten Commandments monument from outside the courthouse. The legal drinking age in Alabama was 19.
She says that Moore drove her back to the same house after dark, and that before long she was lying on a blanket on the floor.
Nancy Wells, Corfman's mother, told the Washington Post that Corfman told her about the encounter more than a decade later. Corfman never filed a police report or a civil suit, the Post said.