The United States and Japan are headed into a time of tribulation due to a paralysis in Japanese politics and President Obama's decision to send an inexperienced and uninformed ambassador to Tokyo.

Japan is scheduled to hold parliamentary elections on Aug. 30 in which the Liberal Democratic Party, which has governed Japan for most of the postwar period, is widely expected to be thrown out. The LDP has lacked leadership and consistent policy for the past three years, during which it has burdened Japan with three prime ministers, four foreign ministers and six defense ministers, none of them effective.

The Democratic Party of Japan, riven with factional disputes and charges of corruption, appears to be in no better position to govern. As the Economist magazine, which has long been critical of Japan, said last week, the DPJ "is an unlikely mix of socialists and former LDP hands without an identity or a coherent agenda."

Into this turmoil will step the new U.S. ambassador to Japan, John Roos, a highly regarded lawyer and fundraiser for Obama in California's Silicon Valley. In his confirmation hearing before the Senate Foreign Relations Committee last week, Roos asserted, "I believe that the DPJ will be equally committed to the strength of the alliance and the bilateral relationship."

That statement, presumably drawn from a State Department briefing, was at best simplistic and evinced little understanding of the dynamics of Japanese politics. Roos added: "The relationships with the United States government are deep on both sides of the aisle," meaning the LDP and the DPJ, of which it is tempting to say, was naive.

Roos' credentials are in sharp contrast to those of most of his predecessors as the U.S. has had a succession of high-powered ambassadors in Tokyo for most of the past half-century. Edwin O. Reischauer, a scholar at Harvard, was considered to be the most prominent "Japan hand" in America in the 1960s. Alexis Johnson and Michael Armacost were professional diplomats with much experience in Asia.

Political leaders who later served as ambassadors in Tokyo included Senate Majority Leader Mike Mansfield, Vice President Walter Mondale, Speaker of the House Thomas Foley, and Senate Majority Leader and White House Chief of Staff Howard Baker. Robert Ingersoll was a senior business executive who had an array of helpful contacts in Washington.

Roos is neither Japan hand nor diplomat nor well-connected in Washington beyond having been an adept fundraiser for the Obama election campaign. Rather, he is like Ambassador Thomas Schieffer, his immediate predecessor, who was a friend of President George W. Bush. Even so, Schieffer was active in Texas politics and served as ambassador to Australia before going to Tokyo.

Roos' prepared statement for his hearing was limited to platitudes that underscored, perhaps inadvertently, his lack of preparation. He pointed to "the special bond between our two countries — a bond that, if confirmed, I will devote myself to strengthening and expanding as we confront today's global challenges side by side." He added: "In particular, I will strive to help strengthen the U.S.-Japan Security Alliance."

A more forthright approach came from Assistant Secretary of State Kurt Campbell, who was asked by a Japanese correspondent about Japanese fears that the U.S. would not maintain its "nuclear umbrella," sometimes called "extended deterrence," over Japan. A failure to do so might cause Japan to acquire nuclear weapons, which would cause an arms race in Asia.

Campbell replied: "Extended deterrence is a clear and enduring mission of the U.S., particularly in Asia. And so you're going to find that almost every senior interlocutor, in his or her meetings with the Japanese or Korean counterparts, underscores the importance of nuclear deterrence and extended deterrence, in the Asian context."

Richard Halloran, formerly a New York Times correspondent in Asia and in Washington, is a writer in Honolulu.