I lived in Iowa and went to the caucuses during the 1980s. You gather in some fire hall or library and count noses after supporters of the various candidates gather in a group. If a candidate has too few supporters they can gather with some other candidate and then there is the nose count. IMHO the process is dumb and open to manipulation. I saw Buchanon supporters being bused into my precinct from out of state. Have a real primary ballot or forget about it. Has the Iowa caucus ever been a bellwether for who gets the nomination?
It started Obola on to the DemonCrap nomination. And he did it by bussing supporters in from IL, the very kind of fraud you were concerned about.