The Independent is reporting that Scarlett Johansson, Amanda Seyfried, Jessica Chastain and Reese Witherspoon "are among actresses being considered" for the movie, which likely means, they are part of a long wishlist that will get whittled down as the project gears up. While we'd wager more of a unknown or perhaps not quite so famous actress is probably the smarter play here, so they can tackle the role without movie star baggage, all that Ponsoldt wants is the right person for the job.
“They’re all wonderful actresses. We’re very fortunate that a lot of really great actors are interested in playing these roles. We’re in an enviable position,” he said. “Regardless of people’s political affiliation or how they feel about Hillary Clinton, you don’t find people who question the quality of her intelligence or her drive. I want a wonderful actress who could embody that.”
It's not clear if the movie has full financing yet -- it was looking for backers when Ponsoldt came on board -- but getting an A-list star and Oscar nominee and/or winner? That would be one way to secure some backers.