“Old men huddled in back rooms smoking cigars has nothing to do with it, although those guys make for great fall men when incompetent candidates fall flat on their faces.”
Old men huddled in back rooms made the rules that allowed cross over voting so that Democrats and liberal Independents could decide the Republican candidate. How do you think McCain won Florida....?
In varies in every state. In some states, it's the state legislature, not party political bosses, that decides if the state's primary is opened or closed. Or, in some instances like California, a popular ballot referendum created the controlling law and in a few other states, judges have actually opened (or closed) the primary system(s).