While we wait for the show to begin, tonight we will look for a few things:
Are the moderates stacking up on the progressives?
The two most prominent progressives, Sens. Bernie Sanders and Elizabeth Warren, will be on stage this evening. You will be surrounded by temperate candidates looking for an outbreak.
It is possible that some of the more centric candidates chase after Mr. Sanders and Mrs. Warren, attacking their liberal vision as unrealistic and expensive.  Some candidates, such as Colorado Governor John Hickenlooper and former Maryland Representative John Delaney, have already used these bumps on the campaign path. These candidates could try to argue that their limited approach to issues such as health care and debt relief is easier to implement, and could address voters outside the Democratic Party in general elections.
In the meantime, Mr. Sanders and Mrs. Warren, who was voted among the top three in most national and state surveys, could point to their massive base support to prove that people are enthusiastic about their plans , Mr. Sanders has received more than 2 million donations and Mrs. Warren has taken over 1
What are the younger candidates doing?
Former Texas representative Beto O'Rourke jumped into the presidential race with much fanfare. After a Senate race in Texas in 2018, however, he had a weak fate, in part with the rise of another young candidate – South Bend, Indiana, Mayor Pete Buttigieg. Mr Buttigieg has entered the race as a relatively unknown candidate, but is constantly in the top 5 and has collected the most money from all candidates in the field.
But both candidates are still single-digit and must pass candidates like Mr. Sanders and Mrs. Warren if they want a better chance of being the candidate.
Is Joe Biden mentioned?
Former Vice President Joe Biden will not be on stage on Tuesday night, but the Democrat leader might perform during the action.
Mr. Sanders and Mr. Biden have been battling each other's health plans for weeks, with Mr. Biden pushing ahead with a plan to strengthen the Affordable Care Act, and Mr. Sanders calling for a complete overhaul of the health care system, which becomes a government health program.
Mr. Biden has also relied on big donors to raise funds for his campaign, a group that both Ms. Warren and Mr. Sanders avoided.
During the recent presidential debate, Californian Senator Kamala Harris went after Mr Biden and saw her collecting donations and intercepting polling. It is possible that some of the lower-class candidates are trying to mimic the success of Ms. Harris by following Mr. Biden's long record, even if he is not on the stage.