I see Carson's support being split but Trump getting very little of it, these are the hard-core social issues evangelicals that are shy about supporting a casino-building Hollywood man who seems to them confused about rudimentary Christianity and to many of them, seems lacking in basic humility (which is part of why they liked Carson and his style --he's the non-Donald). Santorum will pick up a point or two, Cruz a couple, Rubio 3, and a scattering for the rest. Max of 1 for Trump.
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Cruz will take all but a few of Carson’s supporters.
That’ll happen whether or not he drops out.