Passage Summary: Being a good politician requires lying, and lying makes you a bad person. Therefore, you can't be both a good person and a good politician at the same time.

Conclusion: Every effective politician is necessarily a rotten person.

Reasoning: Effectiveness in politics requires deceit, and since deceit is a defining characteristic of rottenness, no honest person can be an effective politician.

Analysis: The author has set up a very rigid, 'all-or-nothing' logical structure: if you are effective, you are deceitful; if you are deceitful, you are rotten. This also implies that if you are scrupulously honest, you cannot be effective. To find what 'Cannot be True,' look for any scenario that breaks these links. For instance, the existence of even one effective politician who is scrupulously honest would completely violate the author's stated rules. In this world, the 'honest politician' is a logical impossibility.