Power—especially the hard variety—is something that by nature has a limited quantity. In fact, by using power, you give all kinds of evidence about how much you really have. Once the OPEC countries demonstrated how they could use oil prices as an economic weapon, the United States learned how vulnerable it was to this tool of extortion, and could it could defend itself through improved gas efficiency, the maintenance of a strategic reserve, and other measures.
The limits of military power, of course, are sometimes the easiest to measure. The Nazi war machine, as fearsome as it was, reached its limits at the English Channel and the Volga River. The frontier of Roman power in Britain had a very visible marker, Hadrian’s Wall.
Governments often choose, however, not to expend their military power to their furthest limits, or even at all. Withholding force maintains the mystery of how much you really have—a question that you may not be able to answer accurately yourself, and certainly don’t want to learn in the worst possible way. Threatening attack, or escalating attack, therefore can be more effective than throwing all the firepower you can at an enemy.
Sometimes, withholding force doesn’t work. Johnson may have thought that the North Vietnamese would have understood how bad things could get if the war continued to proceed up the escalation ladder, so keeping military action at the lower rungs made sense on paper. It didn’t succeed, however, in forcing the North Vietnamese to the negotiating table—though later action, such as the US response during the Easter Offensive, did work. In the 1990s, US air strikes against the Bosnian Serbs and the Serbian government did bring the enemy to the bargaining table, without having to deploy US ground troops.
If you can withhold some or all of the force you can exercise, it’s usually a good idea. Fighting on every front, exercising all of your strength, trying every strategy you have—once you’re done, you’re done.
We’ve currently reached the limits of US military power at the current level of mobilization. After deploying a limited force in Iraq and Afghanistan, the US military has cycled through as many units as it could, kept the Guard units in theater for as long as possible, and cancelled the planned rotations of regular units. Short of a draft, we have no further military strength to bear, unless we start “drawing down” forces in Korea, Europe, or other areas.
The US military has approximately 500,000 active duty (regular) troops, supported by 700,000 reserve and Guard units. Approximately 130,000 are stationed in Iraq, with another 50,000 in Korea, Afghanistan, and Bosnia.
We can feel how badly overextended we are now. In particular, we feel the pinch in areas where we can least afford it. Many units critical to the Iraq and Afghan wars come predominantly from outside the regular units. Approximately 95% of the psychological warfare and civic action specialists, for example, are not regulars. Logistical units, too, often come from the Guard and reserves, which was one of the temptations of “outsourcing” logistical duties to “contractors” (mercenaries) who are increasingly skittish about doing their business in Iraq.
We have, in other words, shown our hand. Not only do we know the limits of our power, so do are adversaries. The North Korean government continues to thumb its nose at us over its nuclear weapons program. Any possible threat to go to war with them over nuclear proliferation—as we did in 1994—is not what it used to be.
Reality doesn’t fit the Richard Perle and David Frum theory: fight a war to show how powerful we are; threaten war with other adversaries; if they aren’t impressed with our power yet, use it on them, too. Repeat this process as often as necessary to end the threats to us.
Leave aside the backlash this approach might create, and the certainty that, even if we were to reinstate the draft, we could not fight every war, everywhere that we feel threatened. The problem of “showing our hand” alone is good reason not to go this route. Our enemies will learn how much strength we have, and how to fight us. (For example, there’s good evidence that the Iraqi insurgents learned from how the Taliban and al Qaeda adapted to US tactics in Afghanistan.)
Showing your hand is a lousy way to play poker, and it’s an abysmal way to protect vital national interests.