There was nothing unusual about the defense arguing that a police officer fabricated a claim of whole cloth, a complete lie. The prosecutor's response was invariably the same: Why would the cop lie?

And indeed, the judge would peer over his spectacles, look down his nose at the defendant and counsel, and admonish them both for their attempt to smear some fine, upstanding defender of truth, honor and law with their scurrilous claims.  Because why would the cop lie?....