Last week, Central Intelligence Agency officials presented lawmakers with a stunning new judgment that upended the debate: Russia, they said, had intervened with the primary aim of helping make Donald J. Trump president.

The C.I.A.’s conclusion does not appear to be the product of specific new intelligence obtained since the election, several American officials, including some who had read the agency’s briefing, said on Sunday. Rather, it was an analysis of what many believe is overwhelming circumstantial evidence — evidence that others feel does not support firm judgments — that the Russians put a thumb on the scale for Mr. Trump, and got their desired outcome…

Representative Adam B. Schiff of California, the top Democrat on the House Intelligence Committee, said the public evidence alone made it clear that Moscow had intervened to help the “most ostentatiously pro-Russian candidate in history.”

“If the Russians were going to interfere, why on earth would they do it to the detriment of the candidate that was pro-Russian?” Mr. Schiff asked.