"I said and believed things that were wrong, and worse, they were very hurtful to people in the LGBTQ community," the presidential hopeful said.
The popular, pro-LGBTQ California senator isn't talking, but sources say she will announce her run on or around the holiday.
The first Democrat to move toward seeking the 2020 presidential nomination has long been a champion of LGBTQ people.
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.