I can give you a list of parameters:
1. Any lie told by a liberal or leftist is “within normal parameters”.
2. Any lie told by a conservative is “outside normal parameters”.
3. Any truth told by a conservative is redefined as a lie, and rule #2 is immediately in force.
4. Any truth told by a liberal or leftist is undefined (like division by zero) as no such case has ever existed or likely ever will exist (although such a case is theoretically possible).
Sounds about right.