HAD JAPANESE VOTERS had a say, their new prime minister would be former foreign minister Seiji Maehara. In a recent poll, Mr. Maehara scored 40 percent — the only one of five candidates to rank in double digits. The runner-ups in the survey were tied at 5 percent.

But the next prime minister was chosen by 398 ruling-party legislators. And they went for someone who polled even below the 5 percenters, finance minister Yoshihiko Noda. Mr. Noda, as The Post’s Chico Harlan reports, campaigned by comparing himself to a loach, an ugly bottom-feeding fish.

“My looks are not great,” Mr. Noda said. “If elected, I wouldn’t have a great support rate.”

Given the disdain in which most Japanese hold both the ruling and opposition parties (with 18 percent and 15 percent approval ratings, respectively) and most of their leaders, that was an odd thing to boast about. But it’s one campaign promise that, if recent history is prologue, seems likely to be fulfilled.

Mr. Noda will take office at a time of perpetual crisis in Japanese politics. Reeling from a massive earthquake in March, an economy that has been underperforming for two decades and a fiscal debt that dwarfs America’s as a share of the national economy, Japan badly needs strong leadership. But Mr. Noda will be the sixth prime minister in five years. One primary task will be simply to avoid the one-year-and-out fate of his ineffectual predecessors.

An illustration of a loach, an ugly, bottom-feeding fish to which Japan’s new prime minister compared himself. (DEA PICTURE LIBRARY/GETTY IMAGES/DEAGOSTINI)

The circumstances of his election don’t bode well. The contest hinged not on issues or leadership ability but on internal feuding involving Japan’s longtime power broker, Ichiro Ozawa, who is under indictment in a fundraising scandal but retains the loyalty of the largest faction of ruling-party legislators. Mr. Maehara, the most popular candidate, refused to buckle to Mr. Ozawa and so proved unelectable. Mr. Noda was not the boss’s first choice, either, but he was less noxious to Mr. Ozawa and squeaked in when Mr. Ozawa couldn’t muster sufficient votes for his own favorite.

To the extent that Mr. Noda has a policy record, it is as a somewhat nationalistic (his victory has set off alarms in South Korea and China) fiscal hawk who will favor an increase in the consumption tax to help pay for earthquake rebuilding and debt reduction. This is a position favored by some economists, who say that Japan simply can’t afford to keep borrowing. But it also could sharpen the contradictions within Japan’s economy, which is already export-addicted and consumption-averse. The merits of the argument may prove irrelevant, since Mr. Noda may not be able to unite his party behind a clear platform, much less steer it through the upper house of parliament, which the opposition Liberal Democrats control.

Japan remains the world’s third-largest economy and America’s most important ally in Asia. Its political paralysis has implications well beyond the island nation of 126 million people. So we hope Mr. Noda can prove the pessimists wrong and slow the leadership merry-go-round. Congratulations to the loach, in other words; long may he rule.