This is a major change in government, with the DPJ ending over 50 years of LDP rule, winning 308 of the 480 seats in the Diet.
I’m not sure how much of this is ideology, and how much is just that the voters were sick and tired of the LDP, which has been an increasingly rudderless bastion of cronyism.
From what I understand of the DPJ, their ideology is not particularly clear either.
They seem to be a bit more assertive on the foreign policy front, and a bit more inclined to developing internal consumer markets, but the differences are not much.
I do think that anti-American sentiment provided some of their votes, and we will see this all over the world for the next few decades, as we continue to feel reverberations of the absolute disgust of the population at US diplomacy under Bush and His Evil Minions&trade.
In many of the industrial democracies, we have an age cohort that has come to political awareness over the past 8 years, and their sense of the US is not as a beneficial influence in the world.
As they move into leadership positions in the next 20-30 years, we will see an increasingly confrontational foreign policy from them.