China's decision to hold a military parade on Sept 3 to commemorate the 70th anniversary of the end of World War II is causing the United States a headache. But the Barack Obama administration needs to show courage to send a high-level official delegation to attend the event even at the risk of offending Japan. More importantly, the US should remind itself of its historical role in healing the wartime animosity between China and Japan at a time when relations between them are strained.

The dilemma for the US, however, is not simple. True, China was the US' main Asian war ally, and millions of Chinese fought alongside American GIs in the China-Burma-India theater of war to stop the Japanese from conquering the entire Asia-Pacific region. And millions of Chinese fell to Japanese aggression during the Chinese War of Resistance Against Japanese Aggression (1937-45).

But much has changed over the past seven decades. From a militaristic autocracy Japan became a pacifist democracy and a close strategic ally of the US, which still has about 100,000 military personnel and their family members in Japan. As the US' third-largest trading partner and top debt holder, Japan is very important for the US economy. In contrast, China-US relations have more or less moved in the opposite direction. For almost the rest of the 20th century after WWII, China was barely relevant on the world stage before re-emerging as a major economic and military power, which many see as a US adversary in the making.