Maybe American lawmakers want to look weak and unimportant. If so, they’re certainly free to do so. But they shouldn’t drag the international prestige of the entire country down to that level.

For example, the Senate plans to debate a “nonbinding” resolution that says President Bush’s plan to send some 21,000 more troops to Iraq is “not in the national interest.” And this resolution is expected to pass.

Wow -- there’s some leadership. Our lawmakers are getting set to say they oppose a policy, but they’re not prepared to do anything to change that policy. Instead of really debating the war in Iraq, our lawmakers will be debating a war in a vacuum. Instead of charting a way forward, they’ll chat senselessly about doing nothing.

Could they possibly make themselves look weaker in the eyes of the world? And there’s a real danger in looking weak. As George Washington said, “there is a rank due to the United States among nations, which will be withheld, if not absolutely lost, by a reputation of weakness.”

That’s a theme Robert Kagan returns to again and again in his new book, “Dangerous Nation,” about American foreign policy up to 1900. Kagan notes that when “other nations believed the United States lacked the power to make good on its commitments, they were more likely to raise a challenge, even in the Western Hemisphere.”

That’s clearly still true today. When the United States seems weak, we invite attacks. This is already happening in Iraq, where Iran is building its reputation at our expense.

We know, for example, that Iran is arming terrorist groups and supporting attacks on U.S. forces. In fact, Iran is helping both Shia and Sunni Muslims, which has helped generate a wider, deadlier war in Iraq.

John Negroponte, President Bush’s pick to be deputy secretary of state, recently underscored Kagan’s point when he told a Senate committee, “If [the Iranians] feel that they can continue with this kind of activity with impunity, that will be harmful to the security of Iraq and to our interests in that country.” Yet we haven’t done anything about it except issue empty threats, such as this one from Sen. Barack Obama, a likely Democratic presidential contender: “If the Iranians and Syrians think they can use Iraq as another Afghanistan or a staging area from which to attack Israel or other countries, they are badly mistaken. It is in our national interest to prevent this from happening.”

That’s true enough, but if our enemies watch us withdraw from Iraq, as the senator wants us to do, those enemies are going to think they forced us to withdraw. They’ll see that as a great victory over the United States. Our enemies will be emboldened, not frightened.

Negroponte also testified that the administration doesn’t “believe that [Iran’s] behavior, such as supporting Shia extremists in Iraq, should go unchallenged.” But, so far at least, it has gone unchallenged. As Kagan shows, similar things have happened before.

During the 1880s, “second-rate powers like Chile could insult and defy the United States with impunity,” he writes -- much as Iran is doing today. “As a result, those who put their fate in American hands … did not fare well, and ardent suitors … came to view America as unreliable.”

This, too, is a very real threat today. The world is watching what we do in Iraq. If we allow the country to dissolve into factional violence, we’ll be handing the Iranians a victory they haven’t earned, and we’ll be showing future potential allies that the U.S. is unreliable.

“Weakness, fear and defenselessness mean war and dishonor,” Kagan quotes Henry Cabot Lodge saying. “Readiness, preparation and courage mean honor and peace.” That was true in the 19th century, and it’s still true today. When the U.S. is seen as being strong, we have fewer problems.

For example, in the second half of the 20th century, the world believed we were strong, and we were able to spread our system around the globe. Because of that, almost every country now has a form of the free market and engages in free trade to at least some extent. But if we were suddenly to be seen as weak, our financial power would be jeopardized just as much as our military power. Before they cast their votes on any meaningless resolutions, all our U.S. senators should thumb through Kagan’s book, and give some thought to whether they’re really acting in our country’s best interests.

They might even be inspired to work to elevate our international prestige, instead of bringing it down.