In 2008, Barack Obama, a freshman Democratic senator, became the first African-American man elected president of the United States. A decade later, another first-term Democrat from the Senate is making a bid for the White House, this time to become the first African-American woman to lead the nation.

Sen. Kamala Harris of California announced Monday on ABC's "Good Morning America" that she is running to unseat President Donald Trump in the 2020 election.

"I feel a sense of responsibility to stand up for who we are," Harris said.

Harris, 54, plans to launch her campaign at a rally Sunday in Oakland, California, where she was born and raised. In 2017, Harris, whose mother emigrated to the USA from India, became the first South Asian-American, and the second African-American female, senator in history, according to her biography on her Senate page.

"The future of our country depends on you and millions of others lifting our voices to fight for our American values. That’s why I’m running for president of the United States," Harris says in a campaign video released on social media.

Before joining the Senate, Harris had already made history as California's first female and first African-American attorney general in 2010. Before that, she served two terms as the district attorney for San Francisco.

As a senator, Harris has been a sharp critic of Trump and his policies. Many predicted for months that she would join the field of Democratic candidates hoping to deny the president a second term.

About a year before the Iowa caucuses, Massachusetts Sen. Elizabeth Warren, New York Sen. Kirsten Gillibrand, former Housing Secretary Julian Castro, Hawaii Rep. Tulsi Gabbard and Maryland Rep. John Delaney are among the other Democrats who have announced their candidacy. Many more are likely to add their names to the list in the coming weeks and months.

Harris sits on four Senate committees, including Intelligence and Judiciary. She made headlines in the latter role after her prosecutorial questioning of Attorney General Jeff Sessions and Supreme Court nominee Brett Kavanaugh.

Her platform proposals include "the largest middle-class tax cut in history," a Rent Relief Act to control housing costs, bail changes and Medicare for all.

Her campaign said that she will not accept corporate PAC money and that she "is committed to returning leadership with honesty and moral character to the White House."

Harris' campaign manager will be Juan Rodriguez, who held the same role in her successful 2016 Senate bid. Her sister Maya will act as campaign chairwoman. The campaign will be based in Baltimore and have a second office in Oakland.

If elected, Harris would become the second president after Richard Nixon to be born in California.

Contributing: John Bacon, USA TODAY; Sam Metz, Palm Springs Desert Sun