Power struggle splits Japan's ruling party

Japan seems destined for a period of political instability as its ruling party embarks on a fierce power struggle to find a successor for outgoing Prime Minister Zenko Suzuki.

An advocate of harmony and consensus in politics, Suzuki quit last week after only two years in office. He had hoped to avert the factional strife that has periodically erupted in his Liberal Democratic Party's ranks.

But several days of intense negotiations have failed to produce one man behind whom the entire party can unite.

Instead, there are now four candidates. They must first undergo a primary election involving the entire Liberal Democratic Party membership of some 1.1 million. The top three vote-getters will then participate in a run-off two days later involving only the party's 421 members of the Diet (parliament).

Party elders, however, have banned campaigning for one week while they make a final attempt to avoid a divisive election. Given the wide differences that have already emerged, this would seem to be a forlorn hope.

The four men seeking the top post are those long expected: Toshio Komoto, in his early seventies, Yasuhiro Nakasone, in his mid-sixties, and Shintaro Abe and Ichiro Nakagawa, both in their late fifties. The general feeling is that only the first two have to be taken seriously, and that Abe and Nakagawa are merely testing the waters for a future premiership bid.

The primary election is reckoned to favor Komoto, who has strong grassroots and business support. But in a vote of dietmen alone, the pendulum would swing back to Nakasone, who can probably rely on the support of the party's ''mainstream'' factions containing about three-quarters of the Diet membership.

The question is whether the Liberal Democratic leadership would regard itself as honor-bound to rally behind Komoto should he prove an outstanding vote-getter in the primary and dispense with a run-off vote that could exacerbate growing differences within the party.

Whoever emerges the winner from the power struggle, the general direction of Japanese politics is unlikely to change radically. The differences between the two leading candidates are really slight ones of emphasis, not opposing political beliefs, befitting a party which has held power for over three decades with no clear-cut ideology to defend at the polling booths.

Mr. Nakasone, Prime Minister Suzuki's right-hand man and preferred successor, is an articulate self-assured veteran politician of more than 35 years, a champion of ''neoconservatism'' and defendant of old-fashioned Japanese nationalism.

He is labeled a hawk, but insists ''I'm a liberal. . . . I want Japan to take a middle course by international standards.'' He is an ardent advocate of constitutional revision ''to preserve the nation's true identity,'' arguing that the present constitution was imposed on Japan by outsiders (the United States) during the occupation and does not truly reflect Japanese national interests.

Part of this revision would be to strengthen the role of Japanese self-defense forces. A former head of the defense agency (and former Imperial Navy officer), Nakasone has long advocated more defense spending - ''not rearmament, but modernization and improvement of the (self-defense) forces so Japan can protect itself against attacks and secure its sea lanes to some extent.''

He has criticized past governments for not doing enough to bolster the domestic economy and alleviate trade friction with the United States and Western Europe, without really revealing what he would do.

On US-Japan relations, he says: ''They are like husband and wife. If there is to be a divorce, it will have to come from the US side.''

One big handicap is his reputation in the party as a man ever ready to change course, advocating different causes at the right time, shifting sides so as always to be on the winning side to advance his considerable political ambitions. This has earned him the nickname of ''political weathervane.''

While Nakasone's ambition shines through constantly, that of Toshio Komoto has been well hidden until recently. A dyed-in-the-wool entrepreneur highly regarded in the business world for his management skills and ability to survive, his political career proceeded quietly for well over two decades until he began to assume important government and party posts in the 1970s. This culminated in a bid for the leadership in 1978, when he came last in a four-man field.

Since then, however, he has worked hard to develop a strong grassroots organization, spending freely of his considerable fortune from stock dealings and his 36-year presidency of a leading steamship company. His knowledge of the business world is now considered an important asset as Japan struggles to escape from a prolonged recession.

Diverging from the austerity preached by Suzuki and Nakasone, Komoto urges heavy government spending to stimulate a business recovery and reduce trade friction. Unless domestic spending picks up drastically and the yen becomes much stronger, all the government's current tariff-cutting and market-opening measures will be useless, he said in a recent interview.

He advocates economic policies that aim to create a more equitable society guaranteeing full employment and to contribute strongly to a world economic recovery. To gladden American hearts, Komoto also favors a considerable increase in defense spending and strengthening of the US-Japan military relationship.

Of the two outsiders, Abe has been long groomed as a prime minister for the 1980s by his mentor, former Prime Minister Takeo Fukuda. A former newspaper political reporter, son-in-law of former Prime Minister Nobusuke Kishi, and the holder of most major party executive posts and government portfolios (including the crucial US-interest ones of international trade and agriculture), Abe is said to have few foes in the party so that his day may not be far off.

He has proved a tough negotiator, giving little away on trade issues with the United States in recent months. But he also says firmly: ''The US-Japan relationship is the axis of our diplomacy, and the pillar of that relationship is the security treaty. . . . Only in that framework can Japan's future as a nation be assured.''

The maverick in the field is undoubtedly Nakagawa, regarded as adding spice to the election proceedings but not much else.

He gained notoriety in the mid-1970s as a founder member of the hawkish ''Seirankai'' group of Liberal Democratic young Turks who once sealed a petition with their blood. The champion of the ultra-right, he wants to abrogate the security treaty with the US to promote national peace and build up an independent military potential.

He argues that it is time for the younger generation to take over and root out the corruption that has accumulated during the party's long hold on power.