Perhaps no one in Asia is happier than Shinzo Abe and his ruling Liberal Democratic Party to see Republicans take over control of the U.S. Congress.

Japan's conservatives tend to prefer their American counterparts, who favor national security and nuclear power — not to mention a strong stance against China. For Prime Minister Abe, the prospect of Mitch McConnell running the Senate must seem like great news for U.S.-Japan relations and his own standing. But there are at least two snags awaiting Abe's administration as Republicans measure drapes on Capitol Hill: a plummeting currency and the Trans-Pacific Partnership (TPP) trade deal, which has stalled in large measure because of Japan's reluctance to open up its agricultural and automotive sectors.

The dramatic move on Oct. 31 by Bank of Japan Governor Haruhiko Kuroda to increase the central bank's already massive bond purchases has driven down the yen to a seven-year low. While that's good news for Japanese exporters, it also threatens to touch off a fresh currency war in Asia.