My own revision of the Buckley rule is to support the candidate most likely to effect conservative change. Again, if you want to “Cruzify” it to swap “issue” for “candidate”, I think that works for my version, too.
From the electoral standpoint, it means don’t give me the guy with the 100% ACU rating unless he can win elections and get people to go along with his agenda. (At the same time, someone who can win elections but doesn’t have conservative ideals is a bad candidate as well.)
From an issue standpoint, it’s taking on not necessarily the most dogmatic topic, but the one where you can “move the needle” or get something accomplished. Seize the opportunities that present themselves, and even in a losing cause on the voting tally, to set the stage for future fights.
There may be a simpler way to get the result. Pick the issue first and then the candidate who expresses it best. The corollary for hopeful candidates is if you express it well, it may be picked as the right issue, and you as the candidate to express it.
Sounds like a good theory but how does it work in practice? Who did you back in the 2012 presidential primary? The people who follow a rule like yours seem to do nothing but pick losing candidates like Dole, McCain and Romney.