For seven decades, the United States has been Japan's most important bilateral ally. During U.S. President Donald Trump's visit to Japan this week, he and newly re-elected Prime Minister Shinzo Abe demonstrated the close bonds their countries share. Nevertheless, changes to the global order in the past several years have raised new questions about the partnership. China's rise to international prominence, for instance, has cast doubt on whether Japan can continue to rely on the United States to guarantee its security. Japan's best strategy for navigating this new phase in geopolitics will be to keep the United States as close as possible while making new arrangements with other countries that can help protect its interests.

An Island Unto Itself

To understand Japan's strategic requirements, one must first consider its geography. The country, a volcanic archipelago situated off Asia's east coast, is a new landmass, having burst from the ocean only in the last 10 million years. Japan has meager deposits of oil, coal and ore, and its distance from the Eurasian mainland has insulated it from outside influences and allowed a strong and singular culture to take form. Its isolation hasn't saved it from turmoil, however; the tectonic fault line that birthed Japan has also subjected it to intermittent disasters, whether earthquakes, volcanoes or tidal waves. Coping with catastrophe has always been part of the Japanese experience.

So has China. For most of the two and a half millenniums of the island nation's recorded existence, Japan's concept of the outside world revolved around its larger neighbor across the sea. It was from China that Japan got its writing system, its political ideas and even the layout of its medieval capital city. When China fell into one of its frequent periods of strife, Japan would simply pull up the drawbridge and focus on its own internal problems.

By the 16th century, the country was just unifying from a period of internecine warfare when the Europeans arrived on its shores. The new shogunate administration decided after careful deliberation that the interlopers, along with their religion, their ideas and their inventions, could cause more harm than good. In response, Japan's leaders sealed their country off from external influence for two centuries. While the Enlightenment and the Industrial Revolution transformed much of the rest of the world, Japan kept to its agrarian roots, blissfully unaware of the handicap its dearth of coal and iron ore deposits constituted.

A U.S. envoy woke the country up to the new global reality in 1853. A few years after the U.S. Congress created the Oregon Territory — and after the California Gold Rush began — President Millard Fillmore sent a fleet of ships to open Japan up to foreign trade. Japan then began to industrialize rapidly, a process that soon revealed the shortcomings in its resource endowment. To secure the resources it needed but lacked, the country began importing them, exporting basic goods to cover the expense. As oil became more and more important in everyday life and industry, Japan's reliance on the United States grew. U.S. imports made up 80 percent of the country's oil supply by the 1920s. But a wealth of resources lay practically at Japan's disposal in China, which at the time was weak and vulnerable. Once again, Japanese leaders turned their attention west.

China now offered an opportunity not only to resolve the country's deficiencies but also to elevate it to the imperial status of its European peers. Japan advanced on its neighbor, starting in resource-rich Manchuria and steadily expanding across China. The encroachment alarmed Japan's fellow great powers and prompted the United States to cut the nation's oil supply. Japan, in turn, seized the oil-rich Dutch East Indies (now Indonesia) and launched the attack on Pearl Harbor. Four years later, however, Japan found itself defeated and occupied for the first time in its history.

Japan emerged from the war chastened, with a new constitution that forbade belligerency. A new global system was taking shape around it, yet the country's strategic considerations were the same as ever. Adapting to the changing circumstances, Japan put its faith in the United States — the center of the new world order — to guarantee its access to sea lanes and to oil supplies in the Middle East. At the same time, it focused on cultivating its economy so that it could pay for the imports it needed. Japan's economy shot up through the global rankings to become the world's second-largest in 1989. And when the Cold War ended two years later, the country — which had been developing its military within the strict limits of its constitution to support the United States against the Soviet Union — relaxed into strategic contentment.

Old Problems, New Challenges

A quarter-century later, Japan is reassessing its position. China has regained its stature over the last three decades, stealing Japan's spot in the global economic rankings thanks to a period of unprecedented growth. Beijing, meanwhile, has been building up its military power, including its navy, and expanding its regional influence, particularly in the South China Sea. Though China's naval power is still no match for that of the United States, it has raised the possibility that one day, the U.S. Navy may face a challenger for control of the seas. For Japan, the prospect is a dangerous one, and one that it needs to start addressing.

Preserving its unfettered access to its sea lanes is still a pressing concern for Japan, which depends on exporters in the Middle East for four-fifths of its oil supply. Since the 1970s, the country had turned to nuclear power as a possible solution to its energy problems, but the Fukushima earthquake in 2011 represented a major setback. The disaster shut down all Japanese nuclear plants, taking 30 percent of Japan's power generation offline in one fell swoop and forcing the country to start importing natural gas and coal as a fallback. (That it could source these commodities from Australia, Malaysia and Indonesia rather than from the Middle East offered small consolation to Japan.) More reliant than ever on energy imports, Tokyo can't afford to lose its critical supply routes. But the United States' security guarantee comes under more of a challenge with each passing year, while China's influence keeps growing. More important, China is one of only three countries in the world that import more oil than Japan does, much of it through the same channels, thus possibly threatening Japanese sea lanes.

To cope with this troublesome situation, Japan has limited strategic options. The country, after all, didn't create the status quo China is now threatening, so it can't do much to maintain it. Furthermore, it lacks the manpower and military capabilities to control its sea lanes without help. The country is home to the world's fastest-aging population that, together with 70 years of self-imposed pacifism, has confined its military to be a small, albeit competent, force. This year, the prime minister announced that his administration would lift the traditional restrictions limiting military spending to 1 percent of Japan's gross domestic product. Even so, the country may not be able to devote enough money to the armed forces to maintain their current limited capabilities, much less modernize and improve them.

Making Friends

Military deterrence, however, is just one way around a crisis. Diplomacy is a more viable option for Japan. The country has long used the asset it has in abundance — capital — to supplement its geopolitical strategies through overseas investment, both public and private. After decades of investment in the countries that make up the Association of Southeast Asian Nations (ASEAN), for example, Japan has won favor with the bloc's members, four of which border the crucial waterway, the Strait of Malacca, that 60 percent of Japanese oil imports must traverse. In the last twelve months, Japan has accelerated its relationship-building endeavors with these nations; Abe has met with Philippine President Rodrigo Duterte four times since he took power in Manila last year in an effort to ingratiate himself and his country with new leader. Japan also signed its first defense initiative with ASEAN last year as part of its charm offensive.

Farther along the route, Japan's burgeoning bilateral relationship with India has received increasing attention in the last year. The pair — two aspiring powers wary of China's rise — make a perfect match, and their relationship looks poised to deepen in the years ahead. Japan has been publicly championing a "free and open Indo-Pacific" policy since 2016. In addition, it joined the United States and India in their annual Malabar naval exercises in 2015 and has been assisting the South Asian country in the military development of the strategic Andaman Islands, located near the Strait of Malacca. Tokyo and New Delhi have also launched a joint economic project to connect South Asia and East Africa through the very same waterways that link Japan and the Middle East. Similarly, Japan and India have both invested in the project to develop the Chabahar port in Iran.

China, of course, is making moves of its own in the region, namely through its sprawling Belt and Road Initiative, a network of infrastructure projects across the Eurasian landmass. The China-Pakistan Economic Corridor, for example, leads to Pakistan's Gwadar port, near the Gulf of Oman, while Sri Lanka's Hambantota port — another of China's development projects — sits close to the Strait of Malacca trade route. What's more, China is making investments of its own to curry favor with ASEAN and to gain influence in Iran. Much as the Russian and British empires vied for control of Central and South Asia during the 19th century, established powers in the region are competing for influence in Eurasia's strategically important territories today.

Plans C and D

Another approach Japan can take to manage the risks to its supply lines going forward is to diversify its energy sources away from the Middle East. The country has already pursued this strategy with Australia, an ally that is all the more important to Japan for its relative maritime strength in the Indo-Pacific. Tokyo even tried to fold Australia into its partnership with the United States and India in 2007 by reviving the Quadrilateral Security Dialogue. Though the structure fizzled soon after, Japan has rekindled the idea, and the four are expected meet on the sidelines of the East Asia Summit next week.

Outside the Asia-Pacific region, Japan is eyeing Russia as a possible partner. Despite its enduring dispute with Moscow over the Kuril Islands, Tokyo stands to benefit from deepening its ties with Russia. For one thing, the country is currently shifting its focus from energy markets in the west to build up the infrastructure necessary to serve importers in the east; Russia plans to be shipping 30 percent of its oil eastward by the end of the year. A proposed pipeline from the Russian island of Sakhalin straight to Hokkaido, moreover, would be a godsend for Japan, offering an energy conduit that doesn't rely on sea routes for the first time in its modern history. For another, forging a closer relationship with Moscow could give Tokyo a way to counter the burgeoning partnership between Russia and China. Drawing Moscow's attention away from Beijing will prove challenging, however — to say nothing of burying the hatchet over the Kurils.

Finally, Japan can take steps to minimize its addiction to fossil fuels to offset its vulnerabilities. The country has demonstrated adaptability and resourcefulness over the years. In the wake of the Fukushima disaster, for example, the Japanese people worked together to reduce their energy demand by taking up more efficient habits. They could doubtless bring their usage down even further should the need arise. Considering that Japan is at the vanguard of emerging technologies, it will be well-positioned to adopt environmentally friendly inventions such as alternative vehicles and energy storage technology. Still, with demand as high as it is in the country, Japan's fossil fuel dependency won't disappear anytime soon.

Against this backdrop, Japan can't afford to neglect its relationship with the United States. In an ideal scenario, the United States would remain both entirely willing and entirely able to guarantee the security of Japan's sea lanes. Failing that, though, Tokyo will need to build a new alliance structure to preserve its position in the emerging world order. Maintaining Washington's interest in the region as it does so will be essential to buy Japan the time it needs for the task. Otherwise, the island country could once again find itself staring down the oil barrel at its deepest geopolitical fears.