Meaning semblance of sanity?

Question

Meaning semblance of sanity?

Answer 1

It's a negative comment that's used to show disdain for the intelligence of others.  For instance:

The voting public shows no semblance of sanity.

Answer 2

This is something that someone would jokingly say to a close friend meaning, e.g., "That sounded so reasonable that I almost forgot you were nuts."

"Semblance of" is the same as "it resembles," meaning it looks like (something else.)