Final voting for the Academy Awards begins Friday and ends Feb. 19.
Biden has been working on mental-health issues as part of the administration's effort to reduce gun violence.
Russell, meanwhile, was on Capital Hill on Thursday to join a bipartisan group of senators in unveiling a mental-health bill that would strengthen treatment options at the community level.
And Cooper was in Washington last week for a press conference to bring attention to mental-health issues. He also visited patients at Walter Reed Army Medical Center.
He said at the time: “If I can do one thing, it is to raise awareness, because I was ignorant before I did this movie.”
Bradley and Russell are the latest line of celebrities stopping in Washington during the Oscar campaign season. "Lincoln" director Steven Spielberg and star Daniel Day-Lewis joined Senate Majority Leader Harry Reid (D-Nev.) and the senators for a screening at the Capital.