You still have got to give credit where credit is due. In these times, Brewer is acting heroically. To second-guess her motivations is a bit petty.
No, it's not petty. It's understanding what it's going to take on the long, rough road ahead. Knowing what you're up against isn't petty, it's smart. I've been let down by RINOs too often.
Yours is exactly the kind of attitude sleazebags incumbents count on. Take McCain for example. Right now he's out there screaming for border enforcement. While that is a good thing, do you really believe he would be doing that if he didn't feel he was being forced to by a tight primary race? Like that old song, if you believe that I have some oceanfront property in Arizona for you.
In Brewer's case yes, what she is doing is excellent. But that doesn't mean that there isn't a possibility she wouldn't have acted if she didn't feel primary pressure.