So far she seems to be the best chance for the GOP keeping AZ. Yes it is always easy to say we need to seat conservatives, but we are reliant upon those who come forward to fill the position. The question in my mind is will the members and majority leader of her party support her? I'm thinking perhaps after her 'ovary' comment, maybe not.
The Rule of Thumb, as defined by William F. Buckley (IIRC) is to vote for the most conservative candidate who can win.
This seat was not a clearly Republican office in the past. When I first moved to AZ, it had been held for years by a Dem named Deconcini, then replaced by a solidly conservative Rep, Jon Kyl. Jeff Flake followed Kyl.
Barry Goldwater held the other seat until he retired and it went to McPain.
Meanwhile, the Governor's seat shifted back and forth.
It's not reasonable to expect a Barry Goldwater clone to win this office now that the state has gone more purple with all the immigrants from liberal states, especially CA. Add to that, the likely Dem candidate has been successful as a House incumbent in Phoenix. Plus, the other most likely Rep candidate is Kelli Ward, who is a "Chemtrails" conspiracy kook with a political tin ear. 84-year-old Joe Arpaio has zero chance of winning the Primary (sub-zero chance in the General), so he must be running as a hobby or something. If she wins the Primary, I think McSally will get the support from the national Party she wants.
So far, unless somebody appears out of nowhere, McSally is the most conservative candidate who can win. The Dem may have downtown Phoenix for a home District, but McSally has Tucson. I've heard Matt Salmon is a possible contender, but he lost his last statewide race against Janet Napolitano (Full disclosure: I worked for him in that Gubernatorial race, and I was disappointed in his lack of "fire in the belly"), and he's vying for being tapped to replace McCain. The State Party is unlikely to want to replace somebody who's actively running for Flakes seat in the middle of the Primaries.