From a speech by Rick Santorum:
"The dangers of carbon dioxide. Tell that to a plant. How dangerous carbon dioxide is."
OK. Experiments prove that too much carbon dioxide causes a plant to grow thin and weak. It looks similar to etiolation and is similarly unhealthy. Said plant is low in nutritive value to herbivores and unhealthy in general.
The idea that if a thing is necessary in moderation, it must be better in excess is typical of poor thought processes and a misunderstanding of the nature of reality. For example, humans must have salt to live, but too much salt will poison a human, causing death. Since Mr. Santorum despises facts and science, and has frequently demonstrated a contempt for reality, his inability to comprehend these facts is unsurprising.
However, we should ask ourselves, is it a good idea to have as our President a man who can't think straight?
Etiolation (pronounced /iːtɪəˈleɪʃən/) is a process in flowering plants grown in partial or complete absence of light. It is characterized by long, weak stems; smaller, sparser leaves due to longer internodes; and a pale yellow color (chlorosis).