In later years, Feinstein faced increasing scrutiny and questions about her age and cognitive abilities, with some observers expressing concerns about her fitness to serve in the Senate.

Feinstein faced criticism from both sides of the aisle for her handling of a letter from Christine Blasey Ford accusing Brett Kavanaugh of sexual assault. Some criticized her for not immediately disclosing the letter, while others criticized her for the way the hearings were conducted.

Feinstein, often positioned as a moderate Democrat, occasionally drew criticism from more progressive members of her party for her perceived centrism and willingness to compromise.