Let's examine this noun "bastard," shall we?
1. a person born of unmarried parents; an illegitimate child.Now, as you have pointed out, #1 does not apply.
2. Slang.
a. a vicious, despicable, or thoroughly disliked person: Some bastard slashed the tires on my car.
However, Slick Willard's tendency to favor bad liberal policy (such as socialized medicine and abortion) IS dispicable, as in: Some bastard stole my liberty (or, in the voice of the unborn: Some bastard stole my life!).
Further, if we examine the word "bastard" in its adjectival function, we see this:
6. spurious; not genuine; false: The architecture was bastard Gothic.Slick Willard, I submit to you, is a spurious, not genuine and false conservative: That Slick Willard is a bastard conservative.
Link.
Well done.
Darn, thought lawyers had a better grip on language than that.