TOKYO -- Days after halting plans to purchase a land-based missile defense system, Japan will begin a formal debate on building capabilities to strike enemy missile launchers as a cheaper, more effective way to defend itself, arguing that such ability does not run counter to the nation's pacifist charter.
The ruling Liberal Democratic Party will start discussions Tuesday as the suspension of the Aegis Ashore missile shield set off a search for an alternative defense system.
The LDP and the government see striking an enemy base when an attack is imminent as part of the nation's right to self-defense and distinguish it from preventive strikes banned under international law.
The government's position was outlined in a 1956 remark by then-Prime Minister Ichiro Hatoyama. "I have trouble believing that the constitution means for us to sit and wait to be destroyed," he said at that time.
Tokyo views its stance as in line with international law. "It's an international consensus that you can exercise your right to self-defense once your opponent readies an armed attack," National Defense Academy professor Masahiro Kurosaki said. Only in Japan would this be up for debate, he added.
Article 51 of the United Nations Charter says: "Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations."
But under customary international law, member nations are expected to exercise the right to self-defense in response to and proportionate to the imminent threat.
Japan has so far refrained from developing the ability to strike enemy bases under its own constitution's Article 9, which states that the country will never maintain any "war potential."
The LDP has long advocated for such capabilities. In 2018, it proposed having the ability to strike enemy bases that have attacked Japan before they can launch a second round of attacks. While the government believes a strike is allowed as soon as the enemy starts preparing its first attack, it thought this scenario would be more palatable for parties reluctant to endorse such a move.
Security threats around Asia have only grown since then as North Korea improves its missile technology and China expands its military presence.
"Public opinion is starting to shift, and we need an organized debate on how much armed capability Japan should have, and why," Meikai University professor Tetsuo Kotani said.
Preventive strikes come in response to not-so-immediate threats and are widely considered a violation of international law. When Israel bombed an Iraqi nuclear reactor under construction in 1981, the United Nations Security Council and other countries denounced the attack.
Section 4 of the charter's Article 2 forbids "the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations."
But it is not always clear precisely what constitutes the start of an attack by an enemy, justifying a strike. "I think we can say an enemy is preparing to attack us once it starts fueling missiles or making other arrangements," then-Defense Agency head Shigeru Ishiba said in 2003.
Japan now has a two-tiered missile defense system, designed to shoot down missiles once they are already in the air. The Aegis Ashore missile shield was intended to provide a third layer of protection. But there was concern within the government and the LDP about its limitations, especially with the low-altitude and hypersonic missiles under development in North Korea and China.
"It would be cheaper to develop strike capabilities than to maintain a general defense," Kotani said. "It would be effective to combine strike capabilities with our existing missile defenses and to cooperate with the U.S. and South Korea."