Obama just sent an email to supporters announcing a speech to be delivered this afternoon. I imagine it will be a message "for" Clinton -- both to support her and to model a coherent pitch for incremental change. There are hints in the letter, highlighted below.
Nine years ago today, I stood on the steps of the Old State Capitol in Springfield, Illinois, to announce my candidacy for President of the United States.
I asked you to join me in taking up the unfinished business of perfecting our union -- to work together to build a better future.
Along the way, Americans like you have done that by playing the most important role in our democracy -- the role of citizen. You've taken on the painstaking work of progress. You've helped us find that middle ground where real change is won -- change like rescuing our economy from the brink of another Great Depression, protecting our planet, and helping millions of Americans gain health insurance.