I think the socialist youth scammed the republican caucus to push for Rubio in Iowa.
The socialist youth were caucusing for Bernie.
I am not surprised that Rubio did so well. I know many people who prefer him, my dad and my husband for starters. They watched the debates and have listened to him speak. They think he is sharp, eloquent, like his policies (and have forgiven him his Gang of 8 transgression), and will contrast nicely against either Bernie or Hillary.