FUTENMA AIRBASE ROW

Tokyo and Washington basically agreed in May to implement a 2006 agreement to shift the U.S. Marines' Futenma airbase to the less crowded Henoko area of Japan's southern island of Okinawa, host to about half the U.S. troops in the country.

But the outlook for implementing the deal is cloudy after then-prime minister Yukio Hatoyama first raised and then dashed hopes of moving the base off Okinawa entirely, angering local residents, who associate U.S. bases with noise, pollution and crime. Hatoyama resigned abruptly in June after his perceived mishandling of the issue sharply eroded his voter ratings.

The dispute over the airbase has distracted the two security allies and could dent the 50-year-old alliance as they try to cope with an unpredictable North Korea and a rising China.

Doubts persist over how much progress can be made ahead of U.S. President Barack Obama's visit to Japan for a Nov 13-14 Asia-Pacific leaders' summit.