Transcript for Will upcoming Democratic debate be canceled because of strike?
Whit, over to you. Now to the Democrats out stumping this weekend taking part in a forum as questions are raised this morning about whether their next debate could be canceled. Our Rachel Scott picks up that part of the story from Pittsburgh. Reporter: This morning, turmoil and uncertainty looming over the next democratic debate. I don't believe we should cross that picket line. Reporter: The debate's location now a rallying point for frustrated union members fighting for better wages and health care benefits. And every candidate who qualified is threatening to boycott. I think it's a terrible look for the democratic party to have a debate that runs a foul of union work rules. Reporter: California labor uniformon unite here 11 sending this letter to the democratic candidates outlining their plans to picket on the campus of Loyola marrimount university. The union is entangled in a labor dispute with a company contracted to handle food services for the university. Just four days out, the DNC is trying to find a way to move forward as planned, releasing a statement saying, while lmu is not party to negotiations, we are working with all stakeholders to find a resolution that meets their needs and is consistent with our values. Having these debates is critical for Americans to see the differences between the candidates. Reporter: Now there are growing calls to lower the threshold for the next round of debates in early 2020. Senator Cory booker's campaign leading the effort after he failed to make the stage, sending this letter to the DNC with the request signed by nine candidates including the early front-runners. Narrowing it too soon, we're not going to hear from everyone and I'm sorry to see that. Reporter: And that letter argues that the current thresholds have prematurely narrowed the diverse field. Well, the DNC is pushing back. They are putting its foot down, and said it will not change its debate criteria for any single candidate even arguing the current qualifications are already extremely low. Eva? All right, Rachel Scott for us out on the campaign trail.
This transcript has been automatically generated and may not be 100% accurate.