23:00

The big question is whether any of that 30%-plus of Republicans who are considered Trump voters have tired of his act. My guess is they have not, and view his continued bellicosity – on display again tonight – as strength.

This was another strong debate from Bush, but it might be too little too late. Cruz started strong with his Scalia question, but seemed to fade.

And, one big question heading into this debate is whether Rubio would find his bearings and shake off the #RubioBot tag. And, it was the old Rubio: he offered smart, concise answers that seemed maybe a bit too smooth but not canned. He was more energetic young McKinsey consultant than Lt Commander Data and, for the most part, he escaped the unpleasant on-stage bickering and stayed out of Trump’s sites.

My grades: Rubio A-; Bush B+; Trump B; Kasich B; Cruz B-; Carson C+. Trump is still the favorite to win South Carolina a week from now, but maybe Rubio and Bush will get a bit of a lift from this debate.