This morning, the New York Times' Maggie Haberman and Jonathan Martin revealed that Elizabeth Warren had a secret meeting with Hillary Clinton back in December. Clinton did not ask for Warren's endorsement, but she reportedly "solicited policy ideas and suggestions" from Warren in what was reportedly a “cordial and productive” meeting.
Due to fundraising considerations, Clinton is not likely to announce her candidacy until April of this year at the earliest. And we have no idea what kind of candidate she's going to be. It's possible Clinton could absorb a lot of Warren's ideas into her platform. Hell, even Jeb Bush is pretending to be concerned about income inequality, so it's not much of a stretch to think Clinton will sound more like Warren this year than she ever has before. But she's also got deep ties to Wall Street that suggest she might not govern like an economic populist.
But Warren's appeal isn't just in her policies. Supporters like the fact that she's a relative outsider to Washington. They like that she isn't connected to 30 years' worth of centrist Democratic Party hacks. They like her speaking style, which is wonky and professorial and passionate. And part of Elizabeth Warren's appeal to some Democrats is that she isn't Hillary Clinton. Even if Clinton does march onstage in April (or whenever) with a full-throated endorsement from Warren, it's likely that not every Warren supporter will support her. In fact, there's a good chance that a majority of Warren supporters might look elsewhere for another candidate to support. This isn't the kind of electoral navigation that can happen in back rooms. Clinton will have to win Warren's supporters by earning them.