Mr Kan had a further dash of good news on November 28th when the incumbent governor of Okinawa, an island in southern Japan packed with American military bases, won re-election.
They helped doom Mr Hatoyama, when he stumbled into a fruitless row with America over the relocation of a marine base in the Japanese island of Okinawa.
Japan's defense ministry said a submarine was spotted by a P-3C Maritime Self-Defense Force patrol aircraft Sunday night passing near Kume Island in Japan's Okinawa Prefecture in the East China Sea.
But the moves - which include closing a key air base and replacing it with a new base in the north of the island - are stalled amid entrenched opposition in Okinawa to the construction of the new base.
The US says it is planning to relocate several thousand marines off Okinawa to Guam, but has linked their departure to progress on a new base in the north of the island - which many residents oppose.