As a Newt supporter, I agree.
As a Newt supporter, I think Newt should stay in...
UNTIL such time as heavy winner-take-all threatens to give Romeny MORE delegates than he would otherwise take with proportional primaries.
As long as Rick and Newt split conservative delegates, these reps at the convention will form a block, and prevent Romeny from taking any brokered convention. (presuming it would go by the 1st vote... otherwise, Newt OR Rick should, at the time it becomes apparent, get out to prevent that).