(Who will be his running mate?)
This border business is not a fraction as important as you apparently assume. I would oppose McCain (as will most Republicans) for his sellout on the judges (rounding up six other quisling Republicans to oppose the nuclear option). I respect him (whatever the problems incurred in the Hanoi Hilton) for his generally meritorious tenure in the Hanoi Hilton, for graduating Annapolis (not always a recommendation: see Jimmuh Peanut) and for an ancestry including a distinguished father and grandfather in US Naval service. None of that merits him the presidency as he has repeatedly demonstrated as a senator.
Our next president will be reliably pro-life and will see to the absolute reform of the SCOTUS, the FedAppeals Courts and the FedTrial Courts. McCain would not be reliable. Our next president will be nationalist and interventionist. McCain who has kissed and made up with the Vietnamese communists is neither. Our next president will not be an eccentric fruitcake of a personality with numbskull public policy positions. That rules out McCain and Tancredo. Our next president will take care of basic business. Ditto.
How many new Mexicans will have to cross that southern border before SCOTUS is under control and abortion outlawed again? I will listen to border issues when Roe vs. Wade is as much an abolished memory as Auschwitz, not before. I am not depending on the Junior League, the yacht club and the polo players to end the American Holocaust and why should I?
As to borders, get in line, take a number and wait your turn until we can get around to it after the abortion and lavender mania issues are dealt with. By comparison to 45+ million slaughtered kids, poor people who are social issue allies coming North does not seem very important.
For those who want social "stability", our status quo stinks. It is time to reshuffle the deck and not to stabilize it.