One theory I heard this morning: If Trump hits Rubio hard, and knocks him out or way down in NH, then Rubio won’t be considered “top 3” anymore. Trump NEEDS Rubio to still be top 3 in SC and in the southern states early in March, since Cruz is so strong and well-organized there. Trump needs it to be a 3-way race in SC and in the south, because he has a better chance in those states in a 3-way race than in another head-to-head against Cruz like Iowa.
Makes sense.