Just after Japan’s diet elected him prime minister, Shigeru Ishiba, not sure he can wield real power or hold his job for long, is calling a snap election for all the seats in the diet’s lower house. That’s because Mr. Ishiba needs the assurance of a solid victory to fortify him against critics within his own Liberal-Democratic Party.

Mr. Ishiba is promising “political reforms immediately, so we can be trusted by the people,” Japan’s Kyodo News reports. The LDP bloc easily elected him prime minister, but the party was divided in the preceding contest for LDP president. Mr. Ishiba will dissolve the current diet next week — a prelude to elections set for October 27 for the diet’s lower chamber, the House of Representatives.

The call for national elections portends a rocky start to Mr. Ishiba’s quest for a panacea for economic problems as well as upgrading of defenses in Asia that may not be in line with the thinking in Washington, Tokyo’s crucial, and only real, ally. American officials have questioned the need for an Asian alliance similar to the North Atlantic Treaty, as suggested by Mr. Ishiba, and wonder about his hints for a nuclear role for Japan.

Mr. Ishiba’s views on defense may not be the immediate reason for the power struggle, much less the scandals that divide the LDP, but they are sure to emerge as critical issues once he’s confident enough of his stability as national leader. The question is whether Japan, given the disaster at Fukushima in 2011, needs nuclear warheads for defense against the region’s three nuclear powers, China, Russia and North Korea.

Mr. Ishiba, a former defense minister, outlined his thinking in a written response last month to questions raised by the Hudson Institute in Washington. “Russia and North Korea have formed a military alliance, and nuclear technology is being transferred from Russia to North Korea,” he wrote. “North Korea is strengthening its nuclear and missile capabilities, and if China’s strategic nuclear weapons are added to these dynamics, the US extended deterrence in the region will no longer function.”

As “deterrence against the nuclear alliance of China, Russia, and North Korea,” Mr. Ishiba explained, “The Asian version of NATO must also specifically consider America’s sharing of nuclear weapons or the introduction of nuclear weapons into the region.”

Mr. Ishiba’s clear statement of the alternatives resembled frequent calls in South Korea for its own nuclear weapons, but he did not hint at cooperation between Tokyo and Seoul on nuclear defenses. That would arouse opposition in both countries. He did, however, propose that Washington and Tokyo upgrade their alliance to  a “special relationship” similar to that between Washington and London.

“The conditions are ripe to revise the Japan-US Security Treaty into a treaty between ‘ordinary countries,’” Mr. Ishiba wrote, while Tokyo and Washington “are deepening security cooperation with South Korea.” Why not, he suggested, station Japanese Self-Defense Forces, the euphemism for the Japanese military, on the American territory of Guam, just as American forces are based in Japan.

The Pentagon has yet to comment on Mr. Ishiba’s proposal, which is sure to ignite a debate between Washington and Tokyo. First, he must deal with matters close to home. Kyodo News, citing Mr. Ishiba’s reputation as a “maverick” who had long sought leadership of the LDP, reported that he was “likely to face a challenging start to his premiership as he seeks to restore voter trust in the scandal-hit ruling party and mend intra party divisions that have deepened since the LDP leadership election.”