Within weeks of 9/11, Japan dispatched ships to the Indian Ocean to provide fuel and other support to the Western forces waging the war in Afghanistan.

It was the first time since World War II that Japan sent forces abroad to support an overseas military conflict, although in a noncombat role. American policymakers hailed Japan as a loyal ally, willing to put "boots on the ground."

Come Nov. 1, however, the Japanese ships will be heading home.

American officials worry that, after taking steps to shed its postwar pacifism, Japan will now shirk its role as an ally in international security.

But these concerns are alarmist. The Japanese government, even its liberal opposition party, has shown a desire and commitment to contribute to global security.

A renewal of the law authorizing the mission in Afghanistan is now increasingly unlikely, since the opposition Democratic Party of Japan (DPJ), which opposes the measure, won a shocking victory in last summer's elections for the upper house of parliament. While the ruling conservative Liberal Democratic Party (LDP) is still determined to reauthorize the military role, it faces significant public opposition and a tough road in the parliament.

Some American officials and experts have issued bellicose warnings that not renewing the mission would signal a dangerous retreat from Japan's responsibilities in the world and undermine the security alliance. Others accused DPJ leader Ozawa Ichiro of being irresponsible, even "anti-American."

These remarks are clumsy and unfair. The possibility of Japan's return to a lesser security role is real enough, but its mission in Afghanistan is the wrong test of the country's reliability as an ally.

In reality, the maritime mission has become largely symbolic. As for Mr. Ozawa, if Americans would listen carefully to his arguments, they would find that he seeks to expand, not contract, Japan's global security role.

What the US sees as backtracking on global responsibility is actually something else --opposition, shared by Japan's liberal and conservative parties, to the American decision to invade Iraq. Once carefully buried behind the appearance of alliance solidarity, it is now surfacing.

Ozawa and his party have been unusually open in questioning the Iraq war, characterizing it as a war without clear international justification. According to reliable accounts, Japanese Prime Minister Fukuda Kazuo privately shares that view, as do others in the LDP.

US officials critical of the DPJ for avoiding a greater security role for Japan should remember that the party supported the antiterrorism law when it was passed in 2001. But they refused to support its renewal later after the Iraq war began. Over time, senior DPJ members say, the mission's original purpose got muddied with military operations in Iraq. Japanese and American officials deny that any diversion took place, but the Pentagon admits that ships engage in multiple missions and there is no way to segregate how fuel is used.

The new version of the law proposed by the LDP explicitly narrows the role of the Navy to supporting antiterrorist interdiction operations, a backhanded acknowledgment that there was no clear separation from the Iraq war.

Ozawa has long advocated a more visible security role for Japan outside its borders, calling on the government to send forces to aid the Gulf War in 1991 and pushing through legislation allowing Japanese participation in UN peacekeeping operations.

Japanese peacekeepers, however, are restricted to noncombat missions. Despite inching toward a larger security role, the government stands by an interpretation of Japan's American-authored antiwar clause in its Constitution that bars the use of force for anything other than to respond to an attack on themselves. But Ozawa has long contended that the constitutional bar should not extend to UN activities.

This month, Ozawa proposed that instead of the maritime force, Japan should send peacekeepers to Afghanistan under the auspices of the UN-authorized international security forces, and to Sudan as well.

Ironically, the ruling conservatives reject that as unconstitutional, arguing it would be an act of collective defense rather than self-defense.

"If Japan is to really be an ally of the US ..." Ozawa wrote, "it should hold its head up high and strive to give proper advice to the US." And in order to do that," he continued, "Japan had to be willing to put itself more on the line by sharing responsibility for peacekeeping, not just sending a few boats out of harm's way."

These are ideas that should be embraced, rather than denounced, by American officials.

Reprinted by permission by the Christian Science Monitor.