Since it was revealed Friday that Virginia Democratic Gov. Ralph Northam’s yearbook page from medical school included a photo of a man dressed in blackface and another person in a KKK robe, incredulous Republicans have been asking: How was it not found earlier?

Ed Gillespie, the Republican who ran against Northam in 2017, declined to comment Monday. But the manager of his campaign, Chris Leavitt, told Fox News that the Republican Governors Association was responsible for opposition research during the campaign, seemingly blaming the organization for apparently not finding the yearbook page.

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"The RGA handled opposition research for our campaign,” Gillespie campaign manager Chris Leavitt said in an email. “Obviously we are surprised that this information was not included in their report but as they did the work, they would have to answer any questions regarding their processes."

A spokesman for the RGA, a well-funded organization dedicated to electing and supporting Republican governors in races across the country, did not return requests for comment on Monday.

Republicans have expressed disbelief that the yearbook page didn’t surface during such a high-profile and contentious contest – especially one where race played a large role.

“Sheer incompetence,” tweeted former George W. Bush speechwriter Marc Thiessen. “Isn't checking yearbook pages opposition research 101?”

President Trump argued over the weekend that Gillespie would have easily won if the “terrible picture” from Northam’s yearbook had only surfaced before the election.

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“Ed Gillespie, who ran for Governor of the Great State of Virginia against Ralph Northam, must now be thinking Malpractice and Dereliction of Duty with regard to his Opposition Research Staff,” the president tweeted Saturday. “If they find that terrible picture before the election, he wins by 20 points!”

The yearbook page could have also been particularly useful to Republicans: Northam and Democrats, during the campaign, used race as a weapon against Gillespie, seeking to tie him to the white supremacist violence in Charlottesville that year. At the time, the Gillespie campaign called it an “ugly character smear.”

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A liberal group called the Latino Victory Fund, which supported Northam, ran an ad at one point showing a pickup truck displaying a “Gillespie for governor” bumper sticker, as children attempted to outrun the driver. It was a reference to the Charlottesville violence, where a white supremacist driver plowed into a crowd of counter protesters.

Also during the campaign, former Hillary Clinton campaign spokesman Brian Fallon tweeted a photo of tiki torch-wielding white nationalists in Charlottesville with the caption: “Live look at Ed Gillespie campaign strategy meeting.”

Mailers funded by the Democratic Party of Virginia also surfaced with Gillespie and Trump superimposed over a photo of the white supremacist protesters. “On Tuesday, November 7th, Virginia gets to stand up to hate,” it read.

When Northam won, California Sen. Kamala Harris tweeted congratulations to Northam for "showing that Virginia won’t stand for hatred and bigotry."

Since the yearbook photo surfaced Friday, Northam has apologized but has resisted calls from nearly the entire Democratic establishment, including 2020 Democratic presidential contenders like Harris, to resign. He has said he doesn’t believe he is one of the people pictured in the photo.