Immigration has a wide range of powers, with almost no third-party organizations overseeing its practices. But it's difficult for foreign nationals' human rights to become an election issue.

long-term detentions of foreign nationals residing in Japan 

The only humane way to deal with this kind of situation is too shorten the detention time of these people significantly by speeding up the procedure to send them back to their home country.

Yeah, dont know about this. In my country, human rights lawyers take cases to court to defend - to be frank - foreign criminals, against deportation after they've committed a string of serious crimes in their host country.

When they win, which is too often, these lawyers countermand the deportation orders which came from the elected government. That ain't right.