Japan's first deployment of Self-Defense Forces - part of an eventual 1,000-troop force - arrived in Iraq this week. This marks an important milestone in Japan's post-war foreign policy as well as the U.S.-Japan alliance. As Japan assumes a role in international security more commensurate with its economic power, the United States should be supportive and seek a strong and reliable alliance between the two countries.

In its most ambitious military operation since World War II, Japanese ground, air, and maritime units begin this week a mission in Southeastern Iraq that will last from six months to a year. The troops, although technically non-combat, will serve on a combat ground zone and be armed as they engage in tasks like establishing water and medical services and rebuilding schools and infrastructure. These forces supplement the $5 billion that Japan has pledged to reconstruction efforts in Iraq.

In contrast to the trepidation expressed by Japan's Asian neighbors at the sight of its troops heading overseas, the view from Washington is a positive one. For the United States, Japan's small military force means far more than the assistance they will provide to the American presence in Iraq. Rather, Japan's contribution is an important diplomatic victory for the U.S.-Japan alliance.

For Japan, the decision to deploy troops was not easy politically, but it was clearly the right one to make given the country's national interests. Japan's economy is almost 90 percent dependent on oil from the Middle East - the largest share of any country - and many Japanese now acknowledge that they must contribute to securing stable oil supplies instead of relying on the United States and other powers.

Indeed, Japan's international and diplomatic presence has not been commensurate with its position as the world's second largest economy in the post-Cold War period. Japan's bitter experience with "checkbook diplomacy" after the 1991 Gulf War - to which it contributed $13 billion but no troops and received little recognition for its efforts - was one important factor in its decision to pursue pro-active involvement in Iraq.

Also guiding this decision is Japan's desire to become a more equal partner of the United States. While some criticize Japan's contribution to Iraq as stemming from obedience to U.S. demands, it should instead be seen as an important act of foreign policy independence. Moreover, Japan's active involvement in Iraq lays the groundwork for future contributions to international security.

In fact, Japan's presence in Iraq is only one aspect of greater cooperation on a range of important security issues with its ally the United States in recent months. Japan's response to threats - not just in Asia, such as in North Korea, but beyond the region to Afghanistan, as well as the global war on terrorism - demonstrates that this alliance will be reliable in times of crises. The United States should do its part to encourage ongoing cooperation with Japan as it faces uncertain threats in the future.

Balbina Y. Hwang is Policy Analyst in the Asian Studies Center at The Heritage Foundation.