New Delhi, Feb. 26 -- Politics have helped dragged the Japanese yen to its lowest in two weeks, but investors shouldn't count on that continuing. Tokyo has a $2.2 trillion backstop for its currency.

The yen fell 0.25% against the dollar on Wednesday, following a 0.79% decline on Tuesday. That put the dollar at Euro156.73, the highest since Feb. 6.

A weaker yen makes Japanese goods, such as cars and tech, cheap in the U.S., while making U.S. exports more expensive in Japan. That combination is sure to upset some people in the White House.

Blame Prime Minister Sanae Takaichi's tightening grip on the Bank of Japan. Her government recently nominated two board members whom the market believes favor low interest rates, and the Mainichi Shimb...