Tokyo — Prime Minister Yasuhiro Nakasone's Liberal Democratic Party has won its most resounding election victory since it was formed 31 years ago. The landslide, which ensures stable conservative rule for at least the next four years, keeps Japan squarely in the Western camp and greatly enhances the ebulliently outspoken prime minister's prestige. But it does not automatically assure him of job security beyond the end of October, when his term as party president expires.
President Reagan can be happy that his good friend Yasu's assertive alliance stance in foreign policy and his efforts to ease United States-Japanese trade friction have not been rejected by the Japanese public.
But Mr. Nakasone's 3 years in office so far have barely seen the beginning of an ambitious effort to turn Japanese society around -- to make it more open, to make its structure less rigid and more flexible, and to give the people not only a greater sense of national pride but a more specific sense of responsibility for the global community.
The Liberal Democrats' landslide is also a personal vindication of the Nakasone administration, since the prime minister campaigned hard on his record.
But he needs a united party to see his program through, and he can achieve this only by appearing humble and by appealing to all factions within his party to look to the future rather than to the dispute-ridden past.
In Sunday's election, the Liberal Democratic Party took 304 of 512 seats in the House of Representatives, which has powers similar to those of Britain's House of Commons. In the less powerful upper house, the House of Councilors, the LDP also won a convincing majority, capturing 72 of 126 contested seats for a total of 141 of the upper house's 252 seats. Among the new councilors will be Nakasone's own son, 40-year-old Hirofumi Nakasone.
Although voter turnout has been higher in some previous elections, the LDP has never won so many seats as it did Sunday.
Party secretary-general Shin Kanemaru is given much credit, in that he boldly trod on some fairly influential party toes to see that official blessing was given only to candidates with a fair chance of winning.
It was not merely the number of LDP votes, it was the effective way in which they were distributed in Japan's multi-seat constituency system, that gave the party its phenomenal victory.
The Japan Socialist Party, the main opposition group, was the biggest loser, plummeting from 112 seats won in the 1983 election to just 86 seats. Party chairman Masashi Ishibashi has worked hard to change the public image of his party as a doctrinaire Marxist bunch, but his campaign failed to catch fire.
Some very hard rethinking is in order for this party, which once commanded the allegiance of one-third of the electorate but now appeals to only one-tenth.
Nakasone will have no difficulty being reelected prime minister when the newly elected Diet (parliament) convenes in a few days. He will then form a new cabinet -- a tricky process. The ruling party's coalition with the small New Liberal Club will almost certainly be dissolved.
Nakasone will have to maneuver among the LDP's five principal factions -- especially the powerful faction of former Premier Kakuei Tanaka, with 87 lower house seats (more seats than the leading opposition party has) -- to show they are valued, without damaging Nakasone's own chances of winning a new term as party president.
Foreign Minister Shintaro Abe has already thrown his hat into the ring, and others may declare their candidacy.
Once the Cabinet is formed, there will be a recess until ``the autumn winds blow,'' to use Nakasone's phrase.
Then will come a special session of the Diet to take up such pet Nakasone projects as privatization of the Japan National Railways. How the prime minister performs in this session will probably determine whether he receives the additional term as party president that he seeks.