I wish, but the assassination attempt will keep quiet the calls for Biden to drop out for a few weeks, and by then it will be too late to get anyone else in before the convention. Biden will have successfully run out the clock on this. He'll have a few more senior moments that alarm people, probably get his ass handed to him again in the second debate, and that will he that. Trump voters will be energized by the assassination attempt, Democrats will be demotivated by an old, out of touch candidate, and American democracy will end.

Sorry for the doomerism. You should still vote, and do everything you can to avert this, but I'm pretty sure this is how it's going to shake out.