Force Akin out and you split the part at a time where it needs to be unified. For better or worse, Akin is the nominee. All we can hope is that he weathers this one and does not make too many more similar mistakes going forward. A lot to hope for, I know, but it is what it is.
The split is already there. Just look at the FR threats on Akin. If he doesn't withdraw, he will become a cudgel against the GOP, not only in Missouri, but nationally. The topic has already made its way into the WH press briefing today. It will be kept alive and used to pound leading Republicans.