[LearsFool]

Therefore, we pick one issue we DO know inside and out, and use that as the litmus test to determine the candidate’s reasonableness, fairness, and logic in the other matters we will vote to entrust to him

Good idea. And what issue (or issues) might provide such insight?

[Sopater]

And what issue (or issues) might provide such insight?

The one(s) we know inside and out... The ones that we think are most important or allow us to best assess a legislator's judgement.

[ctdonath2]

what issue (or issues) might provide such insight?

Considering that the author is one of the nation's leading firearms instructors, his litmus test is the 2nd Amendment.

Like most any litmus test: for that one issue to resolve as desired, a whole lotta other things must likewise be favorable. Full support of RKBA requires an inherent trust of citizens, a recognition of natural inalienable individual rights, a presumption of innocence before guilt, an acceptance of higher morality, etc...all which in turn affect other issues and require their implementation in a form consistent with particular axioms.