Where is the justification for embracing litmus tests?

Earlier this summer, as they had for decades, conservatives stood firm and united against the use of ideological litmus tests for nominees to the Federal bench. Opposition to their use came from a sound understanding of history and the recognition that litmus tests were an assault on the independence of the judiciary. Their use was predicted to lead to a long term degradation of our entire legal system.

This month, a whole lot of conservatives have attacked President Bush and Harriet Miers for failing to pass their ideological litmus tests. My point is not to highlight hypocrisy, but rather to ask a very serious question -- when and why did so many conservatives decide to abandon their previous beliefs and embrace the litmus test?

I would surely hope that this decision to radically alter course came only after some serious reflection. Would someone please direct me to the law review articles and columns in serious journals where the anti-Miers intellectuals explain and justify their departure from their previous position.

Has anyone explained how the use of litmus tests supposedly benefits the national interest? I'm familiar with a lot of the reasons why litmus tests are a terrible idea. I haven't heard or read anyone offer reasons why the benefits from using litmus tests trump the costs. Has anyone in the anti-Miers group done this benefit-cost analysis?

I have to believe they have. I can't imagine them doing what they did to Bush and Miers without thinking this through very carefully. Would someone please give me the links for the reasoned law review articles, the scholarly analyses, or even the op-ed columns where this has been discussed and decided?