Prehistory: You could almost write Japan's entire modern history as the drive for respect from the rest of the world. Starting with the unequal treaties of the mid 19th century, and the Meiji era drive to modernize and industrialize -- fukoku kyōhei [Rich Country, Strong Military] was the equation -- culminating in Japan's evolution into a regional power and full-bore Imperialist state. Japan was a member of the Allies in WWI and participated in the Versailles conferences, which allowed them to shut out Korean and Chinese representatives, and then became an active participant in the Wilsonian diplomacy -- known as "Shidehara Diplomacy" in Japan, after the man who served as Foreign minister and Ambassador to the US for most of that period -- of the 1920s, signing several arms control treaties and the Kellog-Briand Pact and participating in the League of Nations.
Though Japan was a respected regional power, some in Japan felt that the arms control treaties were intended at least partially to contain Japan's power at the second-tier. This was compounded to some degree by growing American anti-Asian sentiment and legislation, which reinforced the sense that Japan needed to be stronger and more respected in order to be treated fairly in the world. This, along with a myriad of other factors, led Japan into Manchurian occupation, an attempt at brute force nationbuilding which caused more problems than it solved. Among other things, the condemnation of the Manchukuo puppet regime by the League of Nations led Japan to leave the League and join up with other expansionist pariah states -- Italy and Germany -- which were on the outs with Wilsonianism. Japanese rhetoric in response to the League's condemnation was harsh -- and correct -- when it pointed out that Western nations had long histories of conquest and atrocities, but that was OK because they were White.
Present: Japan's attempt to unify Asia against Western Imperialism, in support of Japanese wealth and power, under the rubric of the Greater East Asian Co-Prosperity Sphere still resonates in Asia today. Whether it's protests over Japan's textbooks (Note: China's current riots need to be seen in the light of two trends: official support and consent for anti-Japanese historicism; rising rates of domestic disorder in China, mostly ethnic and economic) or official visits to the enshrined war dead (and pro-war museum) at Yasukuni, court decisions against former sexual conscription victims, or just reluctance to sign on to "Yen Bloc" plans, Japan's leadership in Asia has been undercut since the war. Nowhere else in the world is historiography so central to political and international affairs: nobody denies Japan's economic power, but nearly all of Asia believes that Japan's ongoing official refusal to acknowledge past atrocities means that Japan lacks the capacity for moral leadership.
Japan's role in the world continues to be limited by WWII in other ways. In the aftermath of the war, Japan was disarmed not just literally, but figuratively: the US-written constitution includes the famous Article IX, repudiating war and weaponry as tools of international problem-solving. Japanese leaders, particularly PM YOSHIDA Shigeru, premised post-war Japan's national policy on non-militarization, non-entanglement, economic growth policies. Among other things, it makes it very difficult for Japanese troops to participate in UN peacekeeping missions; though they do regularly join relief aid (Africa, Iraq) and monitoring groups (Golan Heights), they go very lightly armed and rely on other UN forces and their own post-war reputation for non-violent generosity for protection.
That hasn't stopped Japan from being an actor on the world stage. Japan is the second-largest economy in the world, and has been sharing the wealth with underdeveloped nations for several decades now, making Japan the world's largest development donor in absolute terms. The US nearly got caught flatfooted, for example, when Japan's government announced a post-Tsunami Indonesian aid package a full order of magnitude larger than our own. And Japan gave the US so much money in support of the first Gulf War against Saddam Hussein in Kuwait -- because they couldn't send military forces -- that we nearly turned a profit. Of course, Japan's economic strength means that economic decisions made in Japan echo around the developed world as well. And in a less official capacity, being members of the only nation to experience atomic bombs as a weapon of war has given Japanese peace activists a status in the world second to none. One of Japan's few Nobel Prizes was the Peace award to Prime Minister SATO Eisaku, for his anti-Nuclear "Three Principles": that Japan will not develop or possess nuclear weapons, or allow them in Japanese controlled territory.
Nor has it stopped Japan from being a significant force in Asian and Pacific affairs. On the plus side is cultural and economic influence in South Korea, economic aid to North Korea, investment and education in China, development assistance in the South Pacific; still, all of that, it could be argued, rebounds to Japan's benefit at least as much as it costs. There are territorial disputes as well, mostly over worthless-looking rock islands of immense strategic and economic importance -- Sakhalin and Kuriles (Russia, with whom Japan still does not have an official post-WWII treaty of peace); Tokdo/Takeshima (Korea); Senkaku/Daiyou (China, Korea, Vietnam, etc. I've long argued that this was the most likely -- after North Korea -- flash point for a regional conflict) -- disputes which seem to be heating up significantly in recent weeks in no small part because of Japanese actions.
Roots of the Future: The present campaign to get Japan on the UN Security Council is the culmination of two decades of diplomatic efforts, going back to the groundbreaking work of PM NAKASONE Yasuhiro, who turned Yoshida's non-entanglement policies on their head. Nakasone's kokusaika [internationalization] campaign seemed unfocused to some, but it really consisted of three crucial components: national pride in economic and cultural achievements, present and past (Nakasone was the first post-war PM to visit Yasukuni); international action both economic and political (Nakasone was an aggressive negotiator and worked hard to present distinctively Japanese views at meetings like G-7 and in the UN, plus his relationship with Reagan, Thatcher, etc); expanding Japan's capacity to understand and influence the world through expanded foreign language and overseas study (this aspect always seemed kind of squishy and multiculturalist, but it was really integral to an expansion of Japanese power in the world). The campaign has been largely independent, though at times there were coordinated efforts with Germany, and has consisted in no small part of leveraging Japan's ODA in places like Africa into UN support.
The present campaign is a very clever one: by including India and Brazil as Security Council candidates, it looks less like a resurgence of the reformed Axis Powers and more like a "Southernization" (to abuse a term), a legitimation of the success of 20th century decolonization and economic globalization. Moreover, including India makes it harder for China to maintain its traditional rejection of Japanese power. Article IX is still a sticky point: maintaining it makes it easier for Japan's former and present competitors to deal with Japan without fear (not entirely without fear: Japan has one of the best-equipped militaries in the world, though it lacks significant force projection capacity), while it hobbles Japan's ability to play a security role (which, since they're looking for a seat on the Security Council, is significant); moreover, the majority of the Japanese population supports retaining the article as is (a bare majority now, whereas before Gulf War I it was an overwhelming one) and Japanese political leadership have been able to slip in more and more militarized activity under UN rubrics over the last decade (it's highly unlikely that the Japanese courts would step in, being very, very conservative with regard to challenging legislative action).
Japan has been a peaceful, responsible, democratic society for over a half-century, and it is an economic superpower. But it has significant historical and ongoing tensions with its neighbors, one of which already sits on the Security Council and has a pretty good claim to being the natural representative of East Asia. On the other hand, it has good relations with the rest of the Security Council membership, and the example of the 1920s-30s suggests to some that trying to "keep Japan in its place" could well produce a nationalistic backlash in Japan that would exacerbate tensions.
[Thanks, Sepoy for suggesting this! Crossposted to Cliopatria]
Addendum: Konrad Lawson has compiled a very impressive list -- with texts and commentaries -- of Japan's leaders attempts to apologize to Korea without entirely losing the support of Japan's nationalistic elements. It complicates somewhat the question of how comprehensive "apology" and "historical recognition" needs to be to satisfy Japan's critics.