Having two candidates facing McKinney is actually better, since it increases the likelihood that she won't get 50%+1 tonight and thus go into a run-off. In the run-off, my understanding is that Republicans who voted in today's GOP primary will not be able to vote, but that Republicans who did not vote today (as well as those who voted in the Democrat primary) *would* be able to vote.
Oh...didn't realize they had that runoff system down there.