Definitely. Here’s what I think the best scenario would be. Biden resigns immediately, not just declines to run. Perhaps he has an apparent serious health issue that normally could result in the 25th being invoked and for the good of the nation, resigns instead. So Harris succeeds him, giving her the incumbency advantage. For best effect in the upcoming election, she’d need to immediately face some crisis, ideally one obviously precipitated by the republicans, and deal with it handily.