Japan is weighing whether it needs to be a major military power in the Pacific again, 70 years after World War Two.

Since the end the war, Japan has interacted with its neighbors through the lens of a bilateral relationship with the United States. Japanese domestic politics either benefited from the arrangement (through a lucrative domestic arms industry that caters to the U.S. military) or were subservient to it (by providing military bases). However, a multi-polar East Asia and new homeland pressures are challenging how Prime Minister Shinzo Abe views his loyalty to the United States.

Behind the scenes of the April 28 Obama-Abe White House summit — which will include a state dinner and a congressional address by Abe — the leaders will wrestle with changes in what has been the strongest bilateral relationship in Asia.

Security issues loom over the U.S.-Japan relationship, particularly each country’s stance toward North Korea. The Japanese public believe that Japanese Cold War-era hostages are still alive in North Korea; returning them home is an emotional issue (think American POWs “left-behind” in Vietnam) and has always moderated the country’s stance toward Pyongyang.

Negotiations with North Korea on the issue have been troublesome for Abe, and he has already been pressed to loosen sanctions. The North Koreans are demanding that ferry service between the two nations resume, after Tokyo shut it down in 2006, in part under U.S. pressure. Abe is faced with American desire for harsher rhetoric against Pyongyang, but fearful of jeopardizing progress on the hostage issue.

The implicit understanding of the broader U.S.-Japan security relationship has been that Japan’s “contribution” would be almost completely financial; Japan pays out billions of dollars to support, operate and maintain the American military bases on its own territory, in addition to land grants and sweetheart leases for military bases. In this context, Abe and his predecessors have for years managed domestic friction, particularly on Okinawa, over the expansion of U.S. bases, and that is not expected to be a major issue when he meets Obama.

Washington now wants Abe to agree to a “collective defense” arrangement similar to NATO, which would see Japan strike back at an enemy that attacks the United States. (The inverse has been true for some seven decades.) If Abe goes along with this arrangement, he would place Japan at even greater loggerheads with China and North Korea, making his own nation subject to retaliation in response to American military actions throughout the region.

Abe would also suffer domestically if he consented to the United States’ demands for collective defense. In mid-March Abe’s own Liberal Democratic Party convened a conference during which party members challenged the wisdom and constitutionality of the policy. Even conservatives who welcome American military support if China moves toward any of the disputed islands in the Pacific are wary of being drawn into some greater U.S.-China regional tussle.

Japan’s economic priorities are also at stake. Abe must decide whether to join China’s new Asian Infrastructure Investment Bank (AIIB). The United States has opposed the bank, arguing that it will undermine the World Bank and Asian Development Bank. But the White House failed to keep allies South Korea, Taiwan and Australia from signing on. Only Japan has so far stood aside, at the cost of further weakening its relations with China.

Japan’s business community, seeking access to the funds and the Chinese markets that AIIB membership will provide, turned up the heat on Abe. “The business community woke up late, but now they have mounted a big campaign for the AIIB which appears to be very effective,” Japanese Ambassador to China Masato Kitera told the Financial Times. Abe will have to choose between disappointing the United States or his own business community.

Some Japanese media are stating Japan “has not yet decided” whether or not to join the AIIB, as opposed to a common line just a few months ago that the country gave a firm “no.” There is speculation that Japan may announce its participation in the new bank as early as this summer.

The U.S.-Japan relationship is also being tested over the Trans-Pacific Partnership (TPP), one of the biggest trade deals in history. The White House is pushing Japan to sign on; doing so would provide significantly higher gains for the United States by busting open Asian markets, freeing some 40 percent of American imports and exports from tariff and non-tariff barriers, and thus weakening the economic power of China in the region. Abe is stuck between pressure to uphold the relationship, and angry opposition from Japanese farmers who enjoy high tariff protection and are desperate to keep the country’s markets closed. Without opting out altogether, the only way for Abe to please his constituents is to carve out an exception for Japanese agriculture. This decision, however, would upset other signatories and chip away at the American desire to create a free trade zone in the Pacific.

A departure from the bilateral relationship presents risks for Japan. Not getting along better with China has benefited Abe and his predecessors, and the dysfunctional nature of the relationship has been made easier by American support. For Tokyo, barely acknowledging hyper-sensitive issues involving other Asian countries — such as the Rape of Nanjing in China, and the so-called “Comfort Women” in Korea — has helped keep a small, rotating group of Japanese political elites in power practically uninterrupted for 70 years.

Hyper-conservative voters are a mainstay of support for Abe and his party. These supporters see apologies for World War Two crimes as pandering to the demands of Japan’s Asian neighbors. What outsiders may see as leftover issues from a distant war are red meat to Japan’s conservative voters, and to the powerful corporate heads who support them.

Japan has also benefited from the bilateral relationship by developing a lucrative domestic arms industry that caters to American needs. For example, Japan is building a $1 billion facility for final assembly of Lockheed Martin’s F-35 fighters, and will play a large role in the maintenance of those jets in Asia.

On the U.S. side, America maintains significant military bases across the Japanese archipelago. These facilities served as staging areas during the Cold War, and today help the United States counter China. Japan supports the American position in most international forums (Japan votes with the United States at the United Nations about as often as most European allies), donates cash to development efforts in Afghanistan, and even sent a symbolic clutch of troops into Iraq in 2004.

Navigating these issues may force America to accept less than what it wants out of Japan. Doing so would avoid putting Abe in so many no-win situations that he loses domestic support, and thus becomes ineffectual. Obama would do well to understand this, and to carefully choose which issues to press.

What was once America’s most stable relationship in Asia is moving into the category of “it’s complicated.”