I think short term the US Treasury market is liquid enough to absorb the selling they may do. Long term US interest rates are hurting and will continue to hurt banks holding this debt, foreign and domestic. 

siggy47

What happens in the macro if they dump US treasuries?  Does that mean we have to raise rates to keep buyers interested?

Feel so bad for the Japanese people.  Wonderful culture but they fucked.

econ

Japanese Yen at Risk of Intervention as Traders Press Bearish Bets

I think the US will do what it can, but I don't know what the consequences will be. 