MSNBC host Mika Brzezinski revealed Monday that Sen. Kamala Harris (D., Calif.) will decide by the end of the year whether she will for president in 2020.

"Democratic Senator Kamala Harris says she will decide whether she's going to run for president in 2020 by the end of this year," Brzezinski said. "The California senator told me during the Know Your Value Conference in San Francisco on Saturday, ‘It's a very serious decision. Over the holiday I will make that decision with my family.'"

"Senator Harris also said that she's aware of the challenges that a barrier-breaking campaign will include," Brzezinski continued, "saying, ‘Let's be honest, it's going to be ugly. When you break things, it is painful and you get cut and you bleed.'"

Harris has made headlines for her questioning tactics on the Senate Judiciary Committee, including for asking the acting director of ICE if he would compare the agency to the KKK. With the GOP victory in the 2018 senate elections, a Democrat on the committee may lose their seat to a Republican. Harris is the most junior Democratic member on the committee and therefore most likely to lose her seat.

Elected to the Senate in 2016, Harris formerly served as California's attorney general.

If she decides to run for president, she'll face what is expected to be a crowded Democratic field. Potential 2020 Democratic candidates include former Vice President Joe Biden, Sen. Sherrod Brown (Ohio), Rep. Beto O'Rourke (Texas), and Harris' fellow Californian, Rep. Eric Swalwell.