I actually expect the democrat to win; I'm not sure why you're calling it a likely loss year.

Oh - I meant in the scenario where Biden has to drop out in the middle, or towards the end, of the campaign. In that situation, the Democrats are almost certainly going to lose.

For simplicity's sake, let's just assume he has a heart attack right before the convention. So now someone has to step into his place - with three months before the general election. That person (other than Harris and possibly Philips) has not been engaged in any sort of national campaign in 2024. They don't have any staff or organization built up in any state other than their home state. They haven't done any fundraising for the campaign, they haven't had any events in any swing states, they haven't even introduced themselves to the country. They have had virtually no interaction with the folks who have been running the campaign for the previous twelve months. Etc., etc., etc.

So if you're Gretchen Whitmer or Josh Shapiro, stepping into the nomination in August is a recipe for disaster. They're going to fail. You can't start running for President three months before the election. Even if it were handed to them, they're going to lose - but seizing the nomination after a brutal and bloody convention floor fight against Harris will be even worse. And remember, most of the delegates are going to be Biden delegates - so they're far more likely than the average Democratic politico to be favorable to Harris. So the fight on the convention floor would be brutal.

They'll come out of August unprepared, underfunded, trying to run a campaign that they didn't build (and isn't built for them), after alienating a big part of the party, and thrown straight into the fire of a Presidential campaign from go. Their performance will end up being atrocious in the best of circumstances, and they're almost certainly going to lose.