Adding Romney would be the dumbest thing Dems could do after how smoothly this transition to Harris is going. It's why I put 50/50 odds on it happening.
Obama will endorse Harris. He waited until the convention to endorse Biden in 2020. It isn't a big conversation. The whole party has gotten behind Harris.
What are the Genocide Joe and Pass the Torch asshats going to do now? My guess is something about Harris locking up the entire black population of California.