Massachusetts Sen. Elizabeth Warren's battle to stop Jeff Sessions from becoming attorney general saw her become a Democratic hero Wednesday after Senate Republicans blocked her from reading a decades-old letter by Coretta Scott King, the widow of Martin Luther King Jr., opposing Sessions' nomination for a federal judgeship. #LetLizSpeak and Silencing Elizabeth Warren were trending on Twitter, fueling longtime rumors that Warren will run for the White House in 2020. 

Warren, who was considered a possible contender for the 2016 election before she endorsed Hillary Clinton, began reading the letter from King about Sessions Tuesday night on the Senate floor. The letter states: "Mr. Sessions has used the awesome power of his office to chill the free exercise of the vote by black citizens in the district he now seeks to serve as a federal judge."

But Republicans cut her short, claiming Warren had violated Senate rules against impugning another senator. It might have been a bad move that only further served to rally support for Warren, a former Harvard law professor who has become a darling of the progressive movement for attacking Wall Street and the Trump administration, including the newly confirmed Education Secretary Betsy DeVos. 

A recent Public Policy Polling poll found Democrats want a younger candidate who has never run for president to enter the race in 2020. But roughly 16 percent said they would back Warren, compared to 31 percent for Joe Biden and 24 percent for Sanders, who have both run for president in the past. 

Like many potential presidential candidates, Warren, 67, is releasing a book about her career in politics this year ahead of the 2020 campaign. Former President Barack Obama had "Dreams of My Father" and "The Audacity of Hope," and former Secretary of State Hillary Clinton published "Hard Choices" in 2014. Warren will release "This Fight is Our Fight: The Battle to Save America's Middle Class" in April. 

“America's once-solid middle class is on the ropes, and now Donald Trump and his administration seem determined to deliver the knockout punch,” Warren said in a statement about the book. “At this perilous moment in our country's history, it's time to fight back."