According to emails contained in the documents, Zach Parkinson, then the campaign’s deputy director of communications, reached out to subordinates on Nov. 13 asking them to “substantiate or debunk” several matters concerning Dominion. The next day, the emails show, Mr. Parkinson received a copy of a memo cobbled together by his staff from what largely appear to be news articles and public fact-checking services.

Even though the memo was hastily assembled, it rebutted a series of allegations that Ms. Powell and others were making in public. It found:

That Dominion did not use voting technology from the software company, Smartmatic, in the 2020 election.

That Dominion had no direct ties to Venezuela or to Mr. Soros.

And that there was no evidence that Dominion’s leadership had connections to left-wing “antifa” activists, as Ms. Powell and others had claimed.