Which promise will Tom keep? I'm confused.
He could keep both, actually. Staying in "to the end" can mean up until a day or two before the election, *then* withdrawing. Or he could stay in and yet still make a public annoucement that he wants all his supporters to vote for Arnold, for the good of California. Either way he'll have stayed in the race until the end, *and* not been a spoiler.
I'm not sure if it'll happen that way, but I'm just pointing out that it's not necessarily an either-or matter on the two promises.