HARRISBURG, Pa. (AP) — Elizabeth Warren’s campaign is moving to become the first in the Democratic presidential primary to hire field staff and open field offices in Pennsylvania. It’s a late primary state that could become an important prize. Warren’s campaign said it has hired a Pennsylvania campaign strategist and will bring on staff and open a field office in Philadelphia in the coming weeks. Pennsylvania’s primary is April 28. It has the fifth-most Democratic primary delegates. Warren may have ground to make up in Pennsylvania. Former Vice President Joe Biden has his campaign headquarters in Philadelphia and deep political inroads in the state.