Twitter initially delayed producing the materials, resulting in a fine of $350,000

There has been open debate within the Democratic party over whether Senator Dianne Feinstein, 90, whose health and cognitive abilities have come into question after a two-and-a-half-month absence due to shingles and other medical complications, should resign.

Questions over Feinstein’s ability to effectively represent California, the most populous US state, have been a sensitive issue for Democrats going back years. As her diminishing health plays out in the public eye there is a renewed urgency to the situation. Riding out her term in absentia until retirement next year is also not a viable option, with Feinstein the tie-breaking vote on the Senate judiciary committee, which holds confirmation hearings for judicial nominees, and effectively the only person who can ensure that Joe Biden’s picks for judges go through.