In the last year of her life, Hannah Arendt offered a retrospective on Vietnam; Home to Roost is printed in the Responsibility and Judgment collection published back in 2003. Her prescient insight was that the entire "not very honorable and not very rational enterprise was exclusively guided by the needs of a superpower to create for itself an image which would convince the world that it was indeed 'the mightiest power on earth.'" Eventually, the war was maintained solely "to avoid admitting defeat and to keep the image...intact."
The official obsession with image developed over time in the Vietnam era. With Iraq, it was central from the beginning. Before the war, Andy Card told Elisabeth Bumiller that "from a marketing point of view, you don't introduce new products in August." Tom Friedman thought invading Iraq would communicate a useful "Suck. On. This." Jonah Goldberg glowingly attributed to Michael Ledeen the idea that "every ten years or so, the United States needs to pick up some small crappy little country and throw it against the wall, just to show the world we mean business." There are countless examples, from high government officials to low pundits, of endorsements of Iraq for the message it would send, as an easy way to dispel the myth of American weakness. The Iraq war is a multi-trillion dollar public relations campaign, aimed at persuading hostile forces of our "strength."
Meyer notes that, insofar as war is used as a signal for will, it requires tremendous message discipline. But as Matt Yglesias points out, such uniformity is effectively impossible in a modern, pluralist democracy -- which is probably why Republican war supporters who are so concerned with the "message" we're sending (to al-Qaeda or Iran or France or whomever) about our "will" have so often resorted to the rhetoric of treason to describe war dissenters, or have engaged in domestic propaganda efforts of questionable veracity (not to mention ethics or legality) to try and keep the American psyche all moving in one public direction.
These are all good points, but Robert Farley, an expert on military affairs, adds that even outside the limitations imposed by American democracy, "signaling" things like "will" relies on several shaky assumptions, which often don't bear themselves out:
1. Signals are unambiguous: The meaning of our signaling is not subject to interpretation, such that different people could, based on different priors, carry away different meanings.
2. Signals always indicate what we want them to indicate: This is related to the first; if we are trying to send a signal of strength, then we send a signal of strength, not a signal of mean, stupid, crazy, etc.
3. We never develop a bad reputation, except for weakness: This is related to the first two; our effort at signaling strength doesn't have reputational costs. If we invade his country, the Other will understand us as strong, rather than as brutal, imperialistic, crusading, evil, etc.
4. No one ever considers that we might be trying to deceive through signaling: This is probably the most important. If signaling is about creating a reputation for strength, and if a reputation for strength is a positive good, then obviously there's an incentive to lie about being strong. The entire premise of signaling depends on no one noticing that we have an incentive to lie about our own strength.
5. We know our own strength: Our effort to communicate the true level of our resolve is dependent on knowing what that level is. However, the resolve of the American people to crush enemies of the American public is a value that is unknown to anyone, including our leadership. At best we're guessing, which basically means that every effort to signal is essentially deception.
This doesn't mean that American actions don't communicate messages that we should be cognizant of. But it does mean that a) we can't pretend like "strength" or "will" are the only signals we'll ever send -- even if that's what we intend to, and b) that it's probably a bad idea to launch entire foreign policy adventures based on the blurry concept of communicating American willpower.