Anchor: Trying to prevent all exchanges of money for political influence would be costly (in terms of liberty as well as of more mundane considerations) and futile.
Entailed: Preventing every exchange of money for political sway would be costly and impossible. 
Contradiction: Trying to prevent every exchange of money for political favors is completely possible. 
Contradiction: You are adult-like in the way you argue.
Contradiction: A woman is wet.
Contradiction: A boy is holding a woman.
Contradiction: A man is climbing a rock wall.