Comment by jltsiren

Japan, among many other countries, subscribes to the idea that the milder law prevails. If an action was illegal but it was made legal after the fact, then it was legal. Similarly, an unconstitutional action can be made constitutional after the fact.

Constitutions are not supposed to be absolute constraints. They are not supposed to prevent a country from doing what is reasonable or necessary, as long as people are willing to accept that it was reasonable and necessary.