 There would be a contested convention with one person needing to get a majority of the delegates, all those backroom sort of conversations that would have to go on like we saw in the old days. If Biden waits until after the convention, the party and Biden can have a little bit more control over who the person would be. They'd avoid a degree of chaos at the convention. But that's still two months from now, and every day that goes by could hurt a potential nominee.