I think I know why the numbers aren’t better for McCain. According to the Rasmussen site these polls were done on Sunday. Now, a lot of Catholics and evangelicals are at church on Sunday, as well as football games, family time, etc. Just the day of the week removes a lot of conservatives from the pool of respondents.
Good point about church goers being polled on a Sunday. It could be enough to change the numbers by a couple of points.
Rasmussen norms for party affiliation, so if he doesn’t have enough Pubbies in his sample, he keeps dialing until he does.
It is axiomatic that Sundays are bad polling days for the GOP.