A drafted letter, circulated by Rep. Jared Huffman (D-Calif.) and obtained by POLITICO, offers the first public signal from Democrats since the weekend's attempted assassination on former President Donald Trump that scores of their own members remain deeply unsettled about the future of Biden's candidacy.

The move comes three days before the Democratic National Convention rules committee is scheduled to meet, when they are expected to vote on setting up the rules and dates for a virtual roll call vote.