NEW: Democrat Senator Elizabeth Warren throws her support behind Zohran Mamdani's government-run grocery stores. Warren says Democrats need to "experiment" with these ideas. "When someone stands up and says, I will lead this city by making it more affordable. And here are my plans, real plans." "Plans to deliver on childcare, plans to deliver on housing, plans to deliver. We're going to experiment. We're going to try things on groceries." "That is the Democratic message."