Massachusetts Sen. Elizabeth Warren , one of most influential leaders in the progressive movement, is being publicly and privately courted by Democrats eyeing presidential bids in 2028 — a sign they're trying to build up their lefty credentials. Why it matters: Progressives are on the rise in the party, and Warren is a key ally to have. She lost her bid for the White House in 2020 but played a major role in shaping Joe Biden's presidency by installing her allies in his administration. Her moves haven't been without controversy. Some centrist Democrats worry that Warren has helped pushed the party too far to the left. Zoom in: Now, Warren's working to put her stamp on the 2028 Democratic primary. She met privately with Kentucky Gov. Andy Beshear for tea this month and has a texting relationship with California Gov. Gavin Newsom , Axios has learned.…