[girigiri]

Editing for minimal change.

"General Election"

The Prime Minister Aso dissolved the Lower House on July 21thst, and a general election will be held on August 30th in Japan.
As you may know, Japanese prime ministers change one after another. are changed in rapid succession.
Mr. Aso took the seat of Prime Minister after two former Prime Ministers’ resignations.
He Mr Aso was elected by LDP (Liberal Democratic Party) members. Almost all the people can’t don't vote when a prime minister is elected, but only ruling Majority Party legislators. (?) can do.
They elect their boss leader, and then drag him down. I guess you would think Japanese people are packs of mutts.
Japanese people don’t attempt a coup d’état nor an assassination. Japanese people are meek, docile and quiet. {へぇえ？｝ I sometimes watch see people in other countries rise against wanton　improper treatment, on TV. If that such energetic people immigrated to Japan, Japan would be occupied over-run by them. I think Japanese politicians may know that, so they ban immigration from other countries.

Correcting to a natural English style.
On July 21st, Prime Minister Aso dissolved Japan's Lower House of Parliament, and a general election will be held on August 30th.
A Japanese Prime Minister is appointed to office by a vote of ((sitting)?) members of the majority party in Parliament; not by general election. I am not sure whether you meant "sitting members of the majority party (in Parliament) select the Prime Minister", or "members of the parliament's majority party select the Prime Minister"
As you may know, a Prime Minister's tenure is usually short: Mr Aso is the third Prime Minister to have been appointed during the latest session, following the resignations of his two predecessors. Parliamentarians elect their leader, only to drag him down. People could be forgiven for thinking of Japanese politicians as just a pack of mutts.
I sometimes see on TV, revolts against corrupt and oppressive governments. The people of Japan, being ...., are not inclined to revolutions or coups d'etat. Could it be that successive Japanese governments have opposed large scale immigration to protect Japan from being over-run by agressive people?

** To some extent, yes. History (pre-Meiji in particular) so attests.**