Japan's cabinet is set to approve on Tuesday a reinterpretation of its pacifist constitution allowing the country to wage war even if it is not under direct attack.
Japan's constitution only allows the country to use force to dispel an invasion of its own territory, but now Tokyo wants to assert its right to so-called collective self-defense, which would allow it to intervene if an ally is in some way under threat.
The move marks a radical departure from the self-imposed restraint that followed Japan's defeat at the end of World War II.
Article 51 of the UN Charter recognizes countries' right to collective self-defense, but Japan had so far opted out, and the move has alarmed neighbors who recall their bitter suffering under the country's wartime aggression.
Critics have warned that a reinterpretation of the pacifist constitution, in which Japan forswears military aggression to settle international disputes, would pose a direct challenge to constitutionalism. But the far-right government of Prime Minister Shinzo Abe says this is merely an attempt to become a more "normal" country and has won U.S. backing for the move.