Not sure. I believe I heard that he has until 5pm tomorrow. I suspect that means that the GOP could still choose another candidate for the ballot. After that, it would take a court action. If someone in Missouri knows for sure, please check in.
A write-in candidate or another Independent would be very problematical.
I hope that the GOP comes up with a quick poll to show this dunce that he does not have a chance. If Akin goes ahead, he will be a pariah and he will be worse than finished in politics.