What We Don’t Know

■ Whether any of the claims in the memos are true. American intelligence agencies have not confirmed them, and Mr. Trump has said they are a complete fabrication.

In addition, one specific allegation — that Mr. Trump’s lawyer Michael Cohen met with a Russian official in Prague in August or September — has been denied by both Mr. Cohen, who says he has never been to Prague, and the Russian, Oleg Solodukhin.

■ Who concocted the information in the memos, if it is entirely false or partly so, and with what purpose. If all the information in the dossier is false, it is a very sophisticated fabrication.

■ What exactly prompted American intelligence officials to pass on a summary of the unvetted claims to Mr. Obama, Mr. Trump and Congress. Officials have said they felt the president-elect should be aware of the memos, which had circulated widely in Washington. But putting the summary in a report that went to multiple people in Congress and the executive branch made it very likely that it would be leaked.

What will happen now?

The F.B.I. has been investigating the claims in the memos, and Democrats are demanding a thorough inquiry into the reports that Trump representatives met with Russian officials during the campaign. But as of Jan. 20, Mr. Trump will be in charge of the bureau and the other intelligence agencies, and he may not approve such an investigation.