Irrespective of monarch or general people, violating it means a violation of sovereign power, and this makes the constitutional system collapse (in this case, sovereign power means state right which shouldn't be [legally] violated in and outside of Japan, and an expression like 'infringement of Japanese sovereignty' is often used in the case of intrusion into territorial waters or abduction of Japanese civilians to other country).
それを犯せば君主であれ国民であれ主権を侵すことになり、ここに立憲制は瓦解する（この場合の主権は、例えば領海侵犯や国民が他国へ拉致された場合などにおいて「我が国の主権侵害」などと言われるが、まさにこの内外に（法律面で）侵されざるべき国家の權利を主権という）。