But the White House has defended Clinton against attacks from Sanders, and Obama has brushed aside concerns about Clinton’s vulnerabilities — including an FBI investigation into her use of a private email server as secretary of State.

“I think Barack Obama has done everything except put a ‘Clinton for president’ lapel pin on his suit,” said Democratic strategist Brad Bannon, who is neutral in the race…

Sanders is vowing to stay in the race all way until the Democratic convention in late July, however, which could keep Obama on the sidelines.

“There’s no way that [Obama] and his team are going to be able to maneuver to isolate Sanders,” said Democratic strategist Jim Manley, who is backing Clinton. “They are going to have to let this play out. I think they’re going to do what they can, given that dynamic, to help her out wherever possible.”