Iowa matters for Republican candidates who need a boost to break away from the pack. Iowa is historically precedent setting.
“Consider a question that doesn't get asked enough: Why does it matter who wins Iowa?
In theory, the answer should be: "because whoever wins Iowa gets Iowa's delegates." But it isn't. The Iowa caucuses award about one percent of the nation's delegates. That's not nothing, but it's not much.”
Via Ezra Klein, Washington Post