Trump has also stated that, by extension, he would retract the American “nuclear umbrella” which protects Japan (through the use of American nuclear weapons) in the instance of an attack: “Well I think maybe it’s not so bad… if Japan had that nuclear threat.” North Korea […] for Japan, is a very valid fear. Removing the protection of the nuclear umbrella could force Japan down the road of internal nuclear development.
If Japan were to be given nuclear weapons or allowed to develop them, countries in the region such as China or North Korea might respond with accusations of encroaching U.S. influence. China, already a nuclear power, could see Japan obtaining or developing nuclear weapons as a direct threat to its own expansion. Although unlikely to cause a “shooting war,” this would surely deteriorate already poor relations. Meanwhile, North Korea could use the move as evidence for their own need to develop nuclear weapons.
[…] Trump’s very first statement on Japan referred to the cost of keeping U.S. bases here. “Of course they [Japan] should pick up all the expense[s]. Why are we paying for this? … I want them to reimburse us.” […] If Trump were to actively demand increased payments, Japan would be faced with a choice: agree to the demands or be faced with large gaps within its military as American troops are forced to leave. […] Japan would be forced to reposition its own armed forces and increase its current military budget.
Underpinning Trump’s bombastic rhetoric is his position on the Japanese Constitution and their ability (or lack thereof) to go to war. “You know we have a treaty with Japan where if Japan is attacked, we have to use the full force and might of the United States… if we’re attacked, Japan doesn’t have to do anything. They can sit at home and watch Sony televisions, O.K.?” […] Many of the right wingers within Japan view Trump as a “once-in-a-lifetime opportunity”, who, if elected president, could provide Japan and Abe with the international legitimacy to finally dismantle Article 9.
Trump has also gone so far as to suggest he would be “…prepared to walk” if North Korea or another country were to attack Japan — effectively breaking the alliance the two countries have had since the 1960s. This would force Japan to, once again, adjust its military capabilities and potentially seek more regional allies, thereby establishing regional and local political blocs.