Furious Democrats accused the committee’s chairman, Representative Devin Nunes of California, of using the committee’s coveted access to classified information for the nakedly political purpose of bolstering Mr. Trump in the face of a criminal investigation. They raced to prepare their own memo, based on the same underlying material, that sought to rebut the Republican claims, and then reluctantly pushed to release it publicly, too. That document is now under review by Mr. Trump, who will decide whether to make it public.

Even some Republicans were distressed by the tactics of Mr. Nunes and his allies and the tit-for-tat cycle they unleashed. Even if the Republican memo raised legitimate points, Mr. Rogers said, “it’s not an investigation if one side just puts out a few facts.”

Top Democratic leaders last week called for Speaker Paul D. Ryan to remove Mr. Nunes as chairman. But Mr. Ryan has stood by both Mr. Nunes and the memo, saying that the document raised legitimate questions about how the F.B.I. and Justice Department used the Foreign Intelligence Surveillance Act, known as FISA, to investigate a former Trump campaign adviser, Carter Page. Mr. Nunes did not reply to a request for comment.

Republicans on the panel say they are also upset with Representative Adam B. Schiff of California, its top Democrat. They see him as all too eager to step before television cameras to hint at evidence — known only to those like him with security clearances — of nefarious links between Mr. Trump or his campaign and Russian operatives.

“I don’t trust Schiff anymore. I just don’t,” said Representative Tom Rooney of Florida. “I don’t know that I can talk to him privately about something that won’t end up on Rachel Maddow,” he added, referring to the liberal host of an MSNBC program.

Nothing better illustrates those suspicions than Mr. Nunes’s decision to erect a partition between the Republican and Democratic staff members.