The American public has shown itself to be quite willing to use force to defend what it perceives as core American interests and values, and at least a large segment reacts suspiciously to communicators who don't seem to share that seriousness of purpose.

The public filters discussion of the use of force through the prism of its very high regard for the U.S. military. The U.S. military is extraordinarily popular and one of the nation's most respected institutions. One important reason may be that, of all our national security structures, the military is the one that most looks like middle- and working-class America. So when you stake out positions on security policy, make sure to signal your high regard for the troops themselves.

At the same time, most Americans also understand the paramount importance of having norms constraining the use of force and tell pollsters that they are quite reluctant to use military force without UN approval. Discussions of the use of force, then, can most usefully be framed as a question of thinking through the consequences of using military force and expanding our options for dealing with crises and threats as part of a global team of allied nations, rather than alone.

The notion of expanding options, not reducing them, is also key to the delicate issue of resources. Calls for cuts in defense can put listeners into a mindset of insecurity, because most citizens take it for granted that any spending on defense will make America more secure. Moreover, critics can easily distort your arguments. Try framing your recommendations in terms of smart choices and the distribution of resources within the defense budget; in terms of how we can more effectively organize our military to address threats; in terms of the distribution of new spending (e.g., how many dollars out of $100 in new money we should spend for each important piece of a comprehensive approach to the problem of terrorism).

Every American president -- like the leaders of every country -- quietly reserves the right to use military force in response to an attack or the threat of one. It only makes sense that, as the UN Charter says, we have the right to defend ourselves when under extreme threat.

• The threat posed by terrorists with a global reach [see What to Do about Terrorism, pages 78-79] means that it is vital for us to be able to go after individuals or groups that threaten us. But the fact that terrorists are global has made it even more important that our response be global and that it have the support of others -- thus taking away support from terrorists.

There is no question about it -- we are the world's preeminent military power. But we're better off when our military doesn't have to carry the whole burden of a conflict like those in Afghanistan or Iraq alone. Senior military officers say that our forces are overstretched and could use help. They also say that the more nonmilitary options available, the easier their job is.

• The more the U.S. points publicly to its military intentions, the more we encourage countries already locked in confrontation -- like India and Pakistan, or China and Taiwan -- to say that they, too, may plan to use military force without provocation.
• We also discourage others from thinking that there is any point in trying to work with us, if we will eventually go off without them. In situations as different as Haiti, the Balkans, and Afghanistan, U.S. determination that military force would be used if necessary and that other countries would be involved as much as possible has produced situations where the U.S. has not carried the whole burden alone.

In the most extreme circumstances,we may not have time to seek support from others. But announcing in advance that we will use force whenever and wherever we choose -- without regard to what others think or the rules we ask others to follow -- may hurt us more than it hurts those seeking to harm us.

• The threat of U.S. preemption already encourages countries like Iran and North Korea to seek nuclear weapons that would make the U.S. afraid to attack.
• Preemption assumes that you have perfect intelligence on who might threaten you, and where and how -- and intelligence professionals will tell you that things are rarely so cut-and-dried.
• Preemption has not stopped attacks by terrorists, who have very little to lose and who operate in diffuse networks that are hard to attack. We have been most effective against terrorists when working with other countries to strike at entire networks, not just a single camp or training site.

Sometimes, force will be the best or only way to respond to a threat or crisis. But a smart policy will put most effort into widening our options, which includes developing policies that will eliminate threats before they require a military response and making sure that we don't have to act alone.

• For example, we can use military and diplomatic tools together to prevent dangerous weapons from ever being built, and see that they are dismantled, instead of having to respond militarily when they are aimed at us. We can help negotiate settlements to local conflicts -- as we did in Macedonia or in Burundi -- before they are such a security threat or humanitarian catastrophe that we have no choice but to send troops.
• Focusing on prevention doesn't close off the option of using force when we need to; but it should make it less likely that situations get out of control in the first place, requiring us to put our troops at risk. In foreign affairs, as in life, an ounce of prevention is worth a pound of cure.