As the Japanese Diet's lower house election is approaching, political parties have plunged into a fanatical campaign with unrealistic notions, especially in the country's foreign policy.

But a collective right deviation in Japanese politics will undoubtedly do harm to its diplomacy and future.

Last week, the U.S. Senate approved an amendment, attached to the national defense authorization bill for 2013, to acknowledge application of a U.S.-Japan security treaty to the Diaoyu Islands.

Propped up by the U.S. move, a number of top candidates for the post of Japan's next prime minister sent out hard-line speeches, including constitution revision and the Self-Defense Forces' upgrade to "national defense forces."

Ironically, Prime Minister Yoshihiko Noda, who is also showing a trend of right deviation, said Monday that he was a "realist" and would push forward foreign and security policies in accordance with "reality."

Noda, also leader of the ruling Democratic Party of Japan (DPJ), should not forget the DPJ's campaign platforms before it came into power that it would spare no effort to build a trusting relationship with China, South Korea and other Asian nations.

The biggest blot of the Noda administration is the "nationalization" of the Diaoyu Islands, an inherent territory of China, by turning a deaf ear to China's strong opposition and abandoning the understanding and consensus reached by the older generation of leaders of the two countries.

The move has not only infringed China's territorial sovereignty, but also hurt the Chinese people's feelings, with bilateral relations down in the dumps and the Japanese economy hard hit.

On Japan's foreign policy, both Noda and his main rivals have disconnected far from reality and given priority to their own parties' interests and electoral advantage.

Furthermore, the political right deviation is continuing to distance Japanese politics from reality, a situation that worries peace-loving people.

On the danger of the political right deviation, some Japanese politicians have also blared out a warning.

Goshi Hosono, policy affairs chief of the DPJ, said the right-wing opinion in the Japanese society, especially on the Internet, is very troubling as it would incite populism and bring Japan toward a dangerous direction.

Former Japanese Ambassador to China Yosuke Nakae said former Tokyo Governor Shintaro Ishihara, who first proposed to "purchase islands," had greatly harmed Japan-China relations and Japan's national interests.

Japanese media have predicted that a new regime led by the Liberal Democratic Party (LDP) will be formed after the general election.

However, no matter which party comes to power, it will face a series of grave challenges, such as economic downturn, low confidence and an irrational populist mood.

With a view to the country's long-term development, Japanese politicians should reflect on history and face reality, instead of going all the way to meet the populist mood and unrealistically flaunting its superiority before others.

The international community hopes that the new Japanese government will handle its relations with China on the basis of a view on the overall situation and history.

The new Japanese government should not play with nationalism driven by political parties' interests and not push Japan along a road of political right deviation, so that the country could avoid becoming an "invisible bomb" that poses a threat to regional and world security and stability.