In a breaking story, the Japan Times reported that in an “unprecedented, grave and serious” threat to Japan, nuclear-armed North Korea test-fired an unidentified ballistic missile that overflew Japan on Tuesday morning.
Whilst there was no damage nor casualties, this was a serious escalation. Although the Japanese prime minister was quickly alerted, it seems that Japan took no evasive action. But Prime Minister Abe quickly phoned President Trump. Since 1951, there’s been the Treaty of Mutual Cooperation and Security between the United States and Japan. After WWII, the US occupied Japan until full sovereignty was returned in 1951. In return for Japan agreeing not the militarize again, the US agreed to defend Japan.
Japan and the US are currently involved in defensive tests, which may have irritated North Korea.
The Japan Times concludes:
The White House has said that all options remain on the table, including military action, stoking concerns of a second Korean War that would devastate the region.