Vice President-elect Kamala Harris submitted her resignation from her seat in the U.S. Senate on Monday, two days before she will be sworn into her new role.

What's next: California Gov. Gavin Newsom has selected California Secretary of State Alex Padilla to serve out the rest of Harris' term, which ends in 2022.

What they're saying: "As I resign from the Senate, I am preparing to take an oath that would have me preside over it," Harris wrote in a farewell post.

• "As senator-turned-Vice-President Walter Mondale once pointed out, the vice presidency is the only office in our government that 'belongs to both the executive branch and the legislative branch.' A responsibility made greater with an equal number of Democrats and Republicans in the Senate," she continued.
• "Since our nation's founding, only 268 tie-breaking votes have been cast by a Vice President. I intend to work tirelessly as your Vice President, including, if necessary, fulfilling this Constitutional duty."

The big picture: Harris will now make history as the first Black, first South Asian and first female vice president when she is inaugurated on Jan. 20. But her exit from the Senate leaves just two Black lawmakers in the chamber, until the newly elected Raphael Warnock (D-Ga.) takes office.

• Harris is one of ten Black lawmakers to have ever served in the Senate, and the second Black woman in the chamber's history.
• Harris will have the power to cast tie-breaking Senate votes upon taking office, writes Axios' Stef Kight. The responsibility has the potential to define her as vice president — and as a possible 2024 presidential contender.

Go deeper: Tie-breaking vote a political challenge for Harris