I think it’s premature for you to have such a defeatist attitude. The general election is over eleven months away, and the current POTUS is weak beyond belief in all the polls, even his own. Hillary would not fare much better if he did step aside (and he won’t), she is tied at the hip to Obama.
It’s very easy to be on the right of either one of them on illegal immigration, and I think they all are. There’s a very good chance the GOP will take the Senate and keep the House regardless of the nominee. The downticket candidates are being overlooked, there’s too many debates, and the GOP had better coalesce around somebody other than Romney by the end of the year.