The Massachusetts senator announces an exploratory committee for a 2020 presidential run.
Democratic House leaders cite claims of election fraud in refusing to seat Harris, who has expressed longing for a time when being gay was illegal.
McSally, who lost to out bi candidate Kyrsten Sinema for one U.S. Senate seat from Arizona, has been appointed to fill the other one.
The New Jersey senator could be first single man elected president in more than 130 years.
Cox, an LGBTQ ally who had the endorsement of Equality California, bested incumbent David Valadao, who had a poor record on queer issues.
As Mississippi agriculture commissioner, the now-senator objected to the hosting of a commitment ceremony on state-owned property.