The first of two Democratic presidential debates starts at 9 p.m. ET tonight. It will be broadcast on NBC News, MSNBC and Telemundo and live-streamed via NBCNews.com.

Sen. Elizabeth Warren will be the only candidate polling in double digits on the first night of the debate. Her greatest competition for air time will be Sen. Cory Booker, Sen. Amy Klobuchar and Beto O’Rourke, none of whom have gained much traction since entering the race.

Other candidates tonight include Mayor Bill de Blasio, Rep. Tulsi Gabbard, Gov. Jay Inslee, Julian Castro, Rep. Tim Ryan and John Delaney.

Leave your reactions in the comments.

DNC Chairman Tom Perez said he’s not worried that the debate between the 2020 contenders will get nasty, The Hill reports.

Said Perez: “We’re going to talk about the issues. There will be nobody talking about hand size. There will be nobody talking about silly nicknames for their opponents, we’ll leave that to the Republicans.”

Steve Israel: “First, the ‘unknowns’ must become known. For candidates polling in the neighborhood of 1 percent, such as Kirsten Gillibrand, Andrew Yang, Eric Swalwell, Tim Ryan, or Bill De Blasio, the debate stage will be a launchpad. They need to make the case to donors, activists, and primary voters that they are viable investments. If they leave the debate the way they came in, as mostly unknown, then they will have lost the debate and likely the race.”

“Second, the ‘knowns’ must remain unscathed. For candidates at the head of the pack, they run with targets on their backs. Joe Biden has the largest target and could find himself playing defense… But Elizabeth Warren has enjoyed a recent surge as a progressive, and there should be no surprise if you see some attempts to blunt her momentum.”

“Third, the ‘known unknowns’ must sink or swim. Candidates like Cory Booker and Beto O’Rourke who have polled somewhere between the top and bottom tiers of the pack will use their moment in the spotlight to offer the public some more compelling rationales for why they should be the Democratic Party nominee. These middle tier candidates will either gas up or sputter out under the pressure of standing out on the debate stage.”

Former Vermont Gov. Howard Dean (D) told the Washington Post that Democrats “won’t win the White House if they nominate two older white men to be president and vice president in 2020, echoing calls by other prominent liberals for the party to embrace diversity on its presidential ticket.”

Said Dean: “If we have two old white guys at the top of this ticket, we will lose.”