One of the reason is election system is bad. People in 1990s wanted to have two big party like US so they introduced single-seat constituency system but it's fa

One of the reason is election system is bad. People in 1990s wanted to have two big party like US so they introduced single-seat constituency system but it's failed. One big party (LDP) and other smaller parties is current situation. One big party don't want to change current system for obvious reason.