A prominent Republican lawmaker criticized on Wednesday the argument that Russian interference in the 2016 presidential election was the reason Donald Trump won.

Presiding over a hearing of the Senate Select Committee on Intelligence, Sen. Richard Burr of North Carolina stressed that Russian subterfuge before and after last November’s election was sweeping and aimed to generally “divide our society.”

“A lot of folks, including many in the media, have tried to reduce this entire conversation to one premise: foreign actors conducted a surgical executed covert operation to help elect a United States president,” Burr said at the Wednesday hearing, where three executives from Facebook, Twitter, and Google testified on their sites’ roles in hosting foreign disinformation. “I’m here to tell you this story does not simplify that easily.”

“This is an incredibly complex story,” he continued. “We can look at the content of the ads and the pages they directed people towards. What we cannot do, however, is calculate the impact that foreign meddling had on this election. It’s human nature to make the complex manageable and determine things that fit your conclusions. That’s bias.”

Burr chairs the Select Committee on Intelligence, one of several congressional organs that have spent months looking into Russia’s role in influencing political discourse in the months leading up to and following the election that saw Donald Trump defeat Hillary Clinton in a startling upset. Some Trump critics have linked his unexpected win to foreign action, especially after it was learned that a former Trump campaign advisor admitted he lied to the F.B.I. about conversations during the campaign with officials linked to the Russian government.

But Burr also dismissed the idea that the parallel inquiries — within Congress and under the aegis of the Department of Justice — were politically motivated — “witch hunts,” as Trump himself calls them.

“This isn’t about re-litigating the 2016 presidential election. This isn’t about who won or lost … this is about a foreign hostile power that tried to divide our society along issues like race, immigration, and Second Amendment rights.”

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