MIAMI (Reuters) - A lot could have gone wrong for Elizabeth Warren at Wednesday’s Democratic presidential debate. U.S. Senator Elizabeth Warren speaks as U.S. Senator Cory Booker and former U.S. Rep. Beto O'Rourke listen at the first U.S. 2020 presidential election Democratic candidates debate in Miami, Florida, U.S., June 26, 2019. REUTERS/Mike Segar It didn’t. Warren, a U.S. senator from Massachusetts, arrived in Miami riding a wave of momentum among the race’s more than 20 candidates.