Gathering my thoughts on the Stevens retirement announcement today, my first concern is for what Justice Ruth Bader Ginsburg told me and my research associate, Gene Schlickman, when we interviewed her for our book in her chambers. Ginsburg said the rift between the liberals and conservatives has widened on the Supreme Court to the point of hurting the cross-fertilization of ideas in handling cases. This is really bad news. The biggest concern of America now regarding the Supreme Court should not be whom President Obama will appoint -- there is little chance he will pick a loser -- but how to heal that rift. Stevens has built bridges for years through the power of his intellect, his ability to discern novel approaches to legal impasses and his ability to communicate quickly, fairly  and gracefully with fellow justices. In that sense, he and his contribution to the Court cannot be replaced any time soon. Obama needs to find a skillful law practitioner who is conciliator, not an ideologue -- that's Stevens's legacy. On a practical point, Obama should start my finding someone who is skillful, incisive and quick writer of legal analysis and interpretation.