Becuase we have horrible leadership. McCain is a very principled guy, but I think he takes the wrong stances on way too many issues. Maybe if we scream loud enough he’ll back down again like he did with the amnesty bill.
He didn't back down from the amnesty bill and still favors granting permanent legal status to the vast majority of illegals here. The lesson he learned, supposedly, is one of sequencing, i.e., first secure the border and then grant amnesty. McCain hasn't changed his views.