Caucus is just Iowa's equivalent of a primary because they're all special snowflakes. No idea why they call it that, I guess it comes from the fact that every county votes on their own and there's no central convention for either party.


A candidate needs 50%+1 of all the delegates. So 1,237 out of 2472 available. Which for Republicans includes 150 superdelegates that can vote however they see fit regardless of the popular vote. Cruz right now has 8, Rubio and Trump have 7 each. None of the superdelegates pledged their support to anyone.
So, basically any of them have a good chance.


If no candidate gets the majority before the National Convention, then they vote at the convention, and keep re-voting (usually by dropping the lowest contenders), until someone does.