If the rule "the condition of the child [should] follow that of the father" were applied to white men and black or part black women during slavery--well, the men might have been breeding themselves into a slave-free society.
Just wait. Ryan will change the "rules" on Trump again at the convention. By the way, nothing is more stupid than Gloria Borger and other saying the rules are the rules and the candidates should have known them. It's as if having a rigged set of rules makes it OK because they have been adopted as rules. Trump, heaven help us, has a good argument that the system is corrupt. Some of us still think that voters should elect politicians, not political hacks.