Sen. Cory Booker (D-NJ) speaks during a news conference regarding the separation of immigrant children at the U.S. Capitol on July 10, 2018.
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Sen. Bernie Sanders (I-VT) claps with a song during the annual Martin Luther King Jr. Day at the Dome event on Jan. 21, 2019 in Columbia, South Carolina.
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Sen. Kamala Harris (D-CA) attends a post-midterm election meeting of Rev. Al Sharpton's National Action Network in the Kennedy Caucus Room at the Russell Senate Office Building on Capitol Hill on Nov, 13, 2018.
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Sen. Elizabeth Warren (D-MA) is pictured during a mock swearing in ceremony with Vice President Mike Pence on Capitol Hill on Jan. 3, 2019.
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TROY, NY - JANUARY 16: Surrounded by her family, Sen. Kirsten Gillibrand (D-NY) announces that she will run for president in 2020 outside the Country View Diner, January 16, 2019 in Troy, New York. Last night on The Late Show, Gillibrand told host Stephen Colbert that she has formed an exploratory committee for her White House run. (Photo by Drew Angerer/Getty Images)
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Howard Schultz, the billionaire former Starbucks CEO, speaks at the Union Square Barnes and Noble bookstore about his new book "From the Ground Up" on Jan. 28, 2019.