Democrats and Republicans alike in the group described watching Mr. Trump as something close to a civic duty, even while they agreed that he was probably appearing at the briefings to help him in a re-election year.

For Americans such as these, many stuck in their homes and trying to make sense of simultaneous health and economic crises they could not have imagined only a few months ago, Mr. Trump’s nightly news conferences have helped give structure to what they described as a series of Groundhog Days spent in anxious quarantine.

They are part of an audience of millions who have watched on broadcast networks, cable news outlets and online since Mr. Trump first made a surprise appearance at a briefing hosted by Vice President Mike Pence on March 14, and decided he liked it.

Mr. Trump’s daily appearances since then, rife with inaccuracies and false claims and laden with grievance and boasts, bear little resemblance in style to President Franklin D. Roosevelt’s fireside chats, the radio addresses during which he tried to soothe an anxious nation through a depression and a world war.

In interviews, Democrats and Republicans alike conceded that the president appeared to be in over his head in dealing with the coronavirus, and that Dr. Fauci and Dr. Deborah L. Birx, the White House’s coronavirus coordinator, were the more reliable voices to listen to for accurate information.

Supporters of the president viewed the crisis as so overwhelming that they were willing to forgive Mr. Trump if he was floundering, because who wouldn’t be, they said. His opponents by and large said they couldn’t think of a person less suited to the moment.