IIRC, Palin’s stated position was she would support conservatives, not just any nominated Republican. She did support the Conservative candidate in the NY 23 District and not the anointed Republican.
I don’t know anything about the particulars concerning AZ or McCain so I won’t say anything but it would be interesting for Sarah to explain what she did and why.
In AZ, there will be a closed Rep primary. There is not a Conservative Party like in NY. In 2008, McCain was the only top tier candidate of either party who failed to win his/her home state by 50% or more in the Presidential primary. McCain is very vulnerable to a strong challgenger. Right now only Chris Simcox of the Minutemen is an announced challenger. JD is leaning towards entering the race.
Sarah is going to be faced with a hard choice on whether to get involved during the primary phase. If she supports McCain against JD, there will be some serious blowback among conservatives. She will have lost credibility. McCain is toxic to any conservative Republican. McCain has already endorsed Crist over Rubio (FL) and Nolan over Tiart (KS) in these senate primaries, i.e., the moderate over the true conservative.