V'tain Tal uMatar: Precision in Halachic Analogies

In an private dialogue we discussed how precise analogies must be in halachah

For a highly imprecise analogy, consider that we use the Babylonian "yardstick" for v'tein tal umatar all throughout the golah even though we are only "bavel" by not being EY! Our agricultural climate is very different

[Same for keeping the highly obsolete nusach of yekum purkan which refers anachronistically to Bavel.]

We are "Bavel" in a sense, but in an imprecise sense.

I made a hilluq hypothesis:
To preserve a status quo, an imprecise analogy might work.

OTOH to make a hiddush might indeed require a higher-level of precision in the analogy.

KT

RRW