Is Heller pure enough to make it through a primary?
Pure in what way? Because I certainly don't think he's been through any massive scandals.
Politically pure, so as to avoid a Tea Party challenger. Has he always been an opponent of recognizing climate change? Not offered proposals on health care prior to 2009 that could be seen as justifying PPACA? Many conservatives said and did things in the mid-2000s that make them potentially unelectable now if the right grass roots constitutional conservative steps up to the plate.
That, I'm not sure of. I'd need to look up his record, since I haven't really cared much about it until now.
A quick glance at on the issues suggests he differs from the typical conservative Republican only on stem cell research. He should be fine, in that case. Though I think I saw a poll that showed Nevada Republicans standing by Ensign. Might just be due to name recognition though.