The resignation of Finance Minister Shoichiro Nakagawa following his disgraceful display in Rome has further weakened Prime Minister Taro Aso and could prove to be the straw that breaks the Cabinet's back, political observers said Tuesday.

"This is the ultimate blow for the Aso administration," said Surugadai University President and political observer Norihiko Narita in Saitama Prefecture. "And there is no doubt that Aso will be held largely responsible for appointing Nakagawa."

Generous TV footage of the finance and financial services minister, known to be a heavy drinker, shows him slurring his speech, yawning with his eyes closed, and having trouble answering reporters' questions at a news conference that was held Saturday after a Group of Seven finance meeting.