Japan’s Prime Minister Shinzo Abe will arrive in Washington next week on an official state visit — including the first address to a joint session of Congress by a Japanese leader in 150 years. President Obama is known for his aversion to such highly formal occasions; there have been very few state visits during his presidency. But sometimes there is such significance attached to a visit by another leader that the trappings surrounding the event must convey it. Official state occasions of this kind generally fall into one of two categories. They can be essentially ceremonial; designed to confirm and celebrate a long standing and important relationship but with little business on the agenda. The most obvious such example would be a visit by Queen Elizabeth. The second category has a real agenda and generally serves to ratify and publicize important agreements between the two governments.

There is no doubt that both governments want Abe’s visit to fit firmly in the second category. The Prime Minister wants nothing less than to ratify a dramatic redefinition of the terms of the U.S.-Japan Alliance making it far more equal, more effective and strategically more consequential that it has ever been — and the White House is fully on board. As evidence of real progress, Abe will underline a recent working level agreement between the two governments to revise something called the Defense Program Guidelines. It sounds bureaucratic and boring (so does the actual text), but for the first time Japan has agreed that its armed forces can come to the aide of U.S. forces under attack near Japan. Believe it or not, until this agreement Japanese military units operated under self-imposed restrictions that forbade them taking action to defend their American allies even is such help was desperately needed. They could only respond to direct attacks against themselves.

This in turn highlights the unique and peculiar nature of this alliance. It was born out of Japan’s defeat in World War II and subsequent occupation by U.S. forces. It is impossible to overstate how traumatic these events (plus Hiroshima and Nagasaki) were for imperial Japan. One result was a profoundly pacifistic population; the Japanese people wanted nothing to do with the use of armed forces as an instrument of national policy. But in a dangerous, predatory, Cold War world, how could Japan possibly survive and function that way? The answer was provided by Japan’s first postwar prime minister, Shigeru Yoshida. His solution was to ally Japan with America and turn over the defense of his country to its conqueror. In return, the United States would be able to use facilities in Japan and station forces there (Marines in Okinawa, for example). Japan became the indispensable base for U.S. security operations throughout Asia. But when it came to actual fighting — in Korea, Vietnam or elsewhere — that was left to the Americans. The Japanese were free to devote their energies to economic recovery and growth. Soon Japanese corporations such as Hitachi and Toyota were the economic juggernauts of Asia and beyond.

Yoshida’s formula worked superbly for six decades. But very recently the strategic landscape for both Japan and the United States has changed fundamentally thanks to China’s dramatically growing military power and assertiveness. For decades Japan has administered some spectacular but uninhabited islands at the southern end of the East China Sea. Over the last five years or so, China has made increasingly bellicose statements insisting the islands belong to China — and has sent ships and planes around and over the islands. Beijing’s recently proclaimed Air Defense Identification Zone includes the islands as part of Chinese territory. The United States is not indifferent to all this because Washington long ago agreed that the U.S.-Japan Security Treaty, obligating the United States to defend Japan, includes the Senkakus. Meanwhile, China’s claim to the South China Sea and its seizure of territory there is a direct threat to Japan because the sea lanes that sustain the Japanese economy run through the South China Sea.

When Prime Minister Abe took office at the end of 2012, he had two major goals: (1) shake the Japanese economy out the zombie-like state it had been in for 20 years, and (2) make Japan a “normal” country with armed forces that could play an active role in support of Japanese interests. That, in turn, required that Japan become a “normal” alliance partner for the United States. So far on the economic front, Abe’s success has been mixed at best. On the “normal country” front he needed to rewrite the terms of the alliance with the United States so that Japan can become an active partner, not just a passive bystander. That is why the “Defense Guidelines” will be major theme of Abe’s address to Congress. Another major theme will be a long pending trade deal, the “Transpacific Partnership” designed to facilitate trade and investment between the UnitedStates and a number of Asia-Pacific countries, but most notably Japan.

As this is written, American and Japanese negotiators are working pretty much around the clock trying to come to an agreement. For the United States, the TPP is more than just trade; it is a vehicle to give this country an assured role in Asia’s economic future at a time when China is, to be blunt, trying to muscle America out of the region. Abe needs the agreement both to anchor America in Asia and to open up his own economy. But Congress, which must ratify any agreement, may not buy any of this.

So when Mr. Abe arrives the stakes will be high and the outcomes uncertain.

The opinions expressed here are solely those of the author.

This article was originally published in the Ellsworth American.