Looking at Japanese-language blogs, you would think that hereditary Diet members are on a par with the Devil's spawn. Of course if the blogosphere were the sole basis of democracy, Ron Paul could be the Republican candidate. And the media is somewhat kinder, but they are still generally unfavorable. In fact, despite such public outcry against nepotism, about a third of the LDP Lower House members are sons (and in rare cases daughters), sons-in-law, and a few brothers, nephews, and grandnephews of former (usually Lower House) Diet members. This is somewhat lower than before the 2005 general election, no doubt because of the expulsion of the Post Office rebels (many of whom did not even make it back to the Diet) and the huge influx of their assassins and other non-pedigreed rookies as the result of the Koizumi landslide victory. The DPJ is not blameless; likely one-fifth or thereabouts of their Lower House members also guard their family heirlooms, including a few from old Socialist Party lineages.
(Oddly, all the convenient online data bases seem to cover the 2003 general election; the only comprehensive post-2005 data base available online is on Wikipedia, which may or may not cover the Upper House as well, and it is too time-consuming for this blogger to confirm it one way or the other.)
Lower House members toil long and hard to cultivate their local constituency. During this process, they build up powerful electoral/political machines around local notables and worthies and just plain enthusiastic people. Of these, the prefectural and municipal assemblymen are of particular importance because of the grass-roots support that they can muster. In fact, they appear to form the nucleus of many, perhaps most, of the prefectural party apparatuses and can on occasion overrule nationally prominent Diet members with impunity. They by no means hold absolute sway over the choice of Lower House candidates, but it is mighty hard to become the next Sultan without the support, or at least acquiescence, of the Janissary.
Over time, I am sure that the relationship can become intensely personal, and thus the electoral/political machine may find it difficult to refuse the last wish of the retiring politician to bequeath his seat to his beloved son or son-in-law (who in most though not all cases will have gone through the name-changing legal adoption process). And the son would more likely than not have served the incumbent father as a political secretary, thus easing the transition. But what of the frantic recruitment of the reluctant offspring or even more distant relative – in the case of sudden intestate, as it were, departure? Is personal loyalty so fungible as to be transferred to persons whose local ties and/or political inclinations are tenuous at best? Why don't the local politicians see this as a chance to stand for themselves?
In fact, I assume that, in many cases, that is exactly what they do. However, it is quite likely that there is no unity within the electoral/political machines behind a single candidate. A battle would disrupt the equilibrium, which, even if restored, would be drastically altered. There will be one mighty winner and his minions on the one side, and there will be losers, large and small. And this would be the case even if there had been a primus inter pares among the politicos to begin with. This looks like a risky proposal for all the members of the machine, not just the main contestants. So here is a powerful incentive to maintain the equilibrium at all reasonable costs. A hereditary successor usually meets this very important, though not essential, condition.
(That same desire, I believe, is the main reason why so many members of the much-maligned central bureaucracy manage to continue to parachute in to run, more often than not successfully, for the governor's office – in some cases whose only link with the prefecture would be a typically two-year term on secondment as a deputy governor (not an electoral office in Japan). The powers-that-be desire to maintain equilibrium; who better to do so than a (hopefully) neutral outsider? Why, then, I ask myself so inconveniently, are there few if any hereditary governors? I suspect that it has to do with the fact that you actually have to govern. Running a prefectural government is not a task for the fainthearted. But I'm going to continue thinking about this.)
I have no way of knowing, or even guessing, whether such a process is good or bad, or that it can be substantially altered. Humans like stability, and there are some very good reasons for it. However, whether those reasons are good for the nation as a whole in the case of political succession in the specific case of the Lower House, I have no idea.
Here, I note that conventional wisdom apparently decries the lack of political vision and reformatory zeal in politics and places at least some of the blame on the preponderance of hereditary politicians. But second-generation Ryutaro Hashimoto matched Yasuhiro Nakasone's scope and depth, if not success, as a reformist Prime Minister. And the man who beat him the second time around, Junichiro Koizumi - so fresh in your memories - is a third-generation Diet member. Second-generation Keizo Obuchi may not exactly have been a reformist, but he succeeded beyond all expectations (actually, there was little, so the bar had been set low, but still…) in steering his administration through the most difficult of economic and political times. The case for the conventional wisdom looks inconclusive.
So I have written all this when I don't even know if it's a good thing or a bad one. But I do believe that I have found a way to look at a very important determinant of the makeup of a very important element of the Japanese political landscape. I also believe that looking at such structural elements is essential, whether your intent is to describe, or to prescribe any aspect of Japanese politics. For example, I intuitively feel that the very size of the DPJ has made a significant realignment of the political parties along ideologically more consistent lines very difficult, and believe that this can be demonstrated by examining both DPJ and LDP within the current electoral rules. I have something like a combination of the thinking in this post and this examination of the New Komeito in mind.
Of course, I may be totally wrong about all this, or, worse, have reinvented yet another wheel, that is, pointed to something that has been obvious to everyone but me or worked over to death by real political scientists. I welcome your suggestions and other comments. If anybody wants to work with me on this in more detail, let me know.
My thanks to Mentor. I now realize that his answer, some time back, to my question was somewhere in the back of my head when I dreamed up this argument.