challenge president obama with some of these younger voters, with independents. that's not what we saw last night. i doubt that's what we'll see if we go through several months of this protracted and ugly primary. >> i think it's a very disappointing performance by mitt romney after all that investment and so many years and that's all he's got to show for it. katrina vandal heuvel, richard wolffe. thanks for your time this evening. remember to answer tonight's question at the bottom of the screen and share your thoughts on twitter @skrn edshow. newt gingrich is going after mitt romney and willing to join forces to take him down. later, i predicted rick santorum would win iowa on monday. well, i was close. he did win the night. just a few votes short. where does santorum go from here? jonathan alter, joy-ann reid and bill burton coming up. stay with us. multi-benefit plus deep clean. you feel it working, so you know you're ready for whatever the day brings. compared to ordinary toothpaste, you feel a deeper clean. up to a two times cleaner feeling.