[Proponents]
MEXT should introduce compulsory English classes into elementary school.
We need to learn English more seriously due to globalization. But Japanese TOEFL average score is the worst among Asian countries. Other Asian countries, e.g. China, South Korea, have already introduced English classes into elementary school.
Another reason is that children can learn proper pronunciation by learning English early.
Some people argue that elementary school children should learn "beautiful Japanese" rather than English, because they are Japanese. But as Goethe said, "He who knows not foreign languages knows nothing of his own." Those who don't study foreign languages can't understand how "beautiful" Japanese is.
[Opponents]
MEXT should not introduce compulsory English classes into elementary school.
Children should learn Japanese rather than English, because they are Japanese. And those who master their native language tend to master foreign language speedily.
Language is basis of thought. If children don't have rich vocabulary in native language, they don't have rich vocabulary to think as well.
Moreover, there is no time to study English for elementary school children. Time to study is limited in school. They should study many kinds of things rather than English. People who speak English fluently but know nothing aren't genuine cosmopolitan.