The shift in ideological profiles in the first two successions must be coincidence, but the Abe-Fukuda-Aso(-Yosano?) succession, I think not. I think that the following has more or less been going on.
There are fairly sizeable numbers of conservative-nationalists and their opposites in the LDP, but my guess is that neither group—I use that word very loosely—is large enough to command a majority. So, when they gravitate toward the most desirable candidate for Party President=Prime Minister in their respective ideological camps, they leave the rest of the LDP Diet members whose top priority is to get reelected—a sizeable majority, I’ll wager—to decide the outcome. This leaves the losing candidate with the momentum and core following to carry him through when the previous winner falters. I suspect that this head start, or the “it’s his turn now” sentiment, is relatively short-lived and will wear off during a long regime like Koizumi’s but can be powerful when the average lifespan of a Prime Minister is about that of a prairie vole*—thus the alternation.
What do you think? Note that although Fukuda did not stand for election against Abe, he was widely seen as the only other candidate who could make a serious run and explicitly declined to stand only very late in the game.
Incidentally, based on this Yomiuri poll, I am hypothesizing that conservative nationalists comprise about one-eighth of the Japanese population. Unfortunately, you need the full results in the hardcopy version to see my point. I’ll try to remember to go over this in a subsequent post.
* To quote Wikipedia:
The prairie vole is a notable animal model for studying monogamous behavior and social bonding because male and female partners form life-long pair bonds, huddle and groom each other, share nesting and pup-raising responsibilities, and generally show a high level of affiliative behavior. However, they are not sexually faithful, and though pair-bonded females usually show aggression toward unfamiliar males, both sexes will occasionally mate with other voles if the opportunity arises.Prairie voles are indeed a useful comparison for human beings.