Dana Goldstein says no:
The Obama team should be pressuring, cajoling, and threatening the Clintons and their machine behind closed doors to drop out well before the convention. But until the voting ends on June 3, Obama should not publicly declare victory unless Clinton agrees to admit defeat. That’s very unlikely to happen as long as she continues to win primaries; she’s just too focused on finishing the process. And it’s true that people in the late voting states are mobilized and excited. Why tramp down on their engagement?
The Dish 