Kennedy made the announcement Tuesday at an event in Oakland, where Shanahan grew up in poverty with her mother, who emigrated from China, and her father, who had a substance abuse problem and suffered from mental disorders.

Shanahan, a lifelong Democrat, told Newsweek she has grown disillusioned with the party over what she sees as a lack of progress on environmental issues and children's health, and because it has helped to rack up a $34 trillion national debt and has no strategy to secure the southern border.