There’ll be a postmortem today at the White House and in Chicago over Obama’s strange out-of-body appearance in the first presidential debate with Mitt Romney last night.

This was not the president we knew. Someone on Twitter remarked that it was weird to see him without a teleprompter. The man who can electrify audiences, even on the campaign trail, looked tired, distracted and listless. During most of the 90-minute debate he retired behind his podium, taking notes while Romney spoke. When it was his turn to speak, he addressed moderator Jim Lehrer, not the challenger for the White House.

He only came alive in the second half of the debate, like a prizefighter on the ropes trying to land a few punches, which were deflected by the well-prepared Romney. But it was too late. Viewers’ impressions would have been cemented in the first few minutes.

So when the questions are asked about what went wrong, here’s an answer. The Obama campaign picked the wrong man for the president’s prep partner, Sen. John KerryJohn Forbes KerryFor the sake of national security, Trump must honor the Iran deal Bernie Sanders’s 1960s worldview makes bad foreign policy DiCaprio: History will ‘vilify’ Trump for not fighting climate change MORE (D-Mass.). In his long, meandering answers, the president at times sounded like the unsuccessful Democratic candidate for the presidency in 2004.

Maybe it seemed like a good idea at the time to pick a Democrat from Massachusetts to stand in for the former governor of the state. It doesn’t look like a good idea now. Obama needs to swap his prep partner, and fast.