President Obama is being pushed by some to quickly approve the deployment of more troops to Afghanistan. At the same time, others are demanding a plan for the speedy removal of U.S troops already there. So far, he has refused to be rushed into an important judgment that will have profound consequences for our country.

Afghanistan has been characterized as a war we should have been fighting all along. It can be argued that near the top of the Bush administration's stunning list of foreign policy blunders was the decision to start moving troops, equipment and most of our attention from Afghanistan to prepare for an invasion of Iraq. However, military victory in Afghanistan is not simply a matter of reappearing now with enough troops and the right military strategy. Afghanistan did not come with a pause button to freeze the action until we were ready to resume. Any such notions are seriously naive.

To begin with, Afghanistan is a honeycomb of ethnic groups and tribes. About half its people are Pashtun, but with primary loyalty to more than 30 different tribes; another 25 percent are Tajiks; 18 percent Hazaras; 6 percent Uzbeks; 3 percent Turkmen; 1 percent Qizilbash; and about 7 percent are Aimaq, Arab, Kirghiz, Wakhi, Farsiwan, Nuristani, Baluch, Brahui, Qizilbash, Kabuli or Jat.

President Hamid Karzai's "national" government has very little to do with the lives of the Afghani people outside Kabul, and isn't even recognized in every sector of that city. Classic counterinsurgency doctrine depends on an indigenous government we can support, but the current national government in Afghanistan doesn't remotely qualify, unless one considers an isolated, corrupt government "worthy."

The presence of U.S. troops in Afghanistan is a two-edged sword. They may be utilized to suppress violence and impose civil order in limited areas, but their presence is often the spark that ignites the same violence and resistance. No people willingly submit to be patrolled or garrisoned by a foreign military. Our own founders didn't take very well to it 234 years ago. Afghan culture has always opposed the presence of large numbers of armed outsiders, and with the continuation of combat, killing of civilians and destruction, our troops are being increasingly viewed the same way that Macedonian, British and Soviet troops were.

Before the United States commits to a military strategy, Obama needs to take the time to review the history and contemporary culture of Afghanistan. Against a backdrop of knowledge, there are a number of very practical questions about our expectations there that must be asked — and answered, including:

• What can be realistically achieved? What kind of Afghanistan can we realistically leave behind?

• Does it have to be a working democracy with freely elected officials and a centralized government, i.e. full-on nation building?

• Would it be sufficient to leave a region able to deny terrorists safe haven?

• Is such a goal possible with military action? If so, how many years or decades will it require?

• What agreements with Pakistan will be necessary to curb or end the ability of al-Qaida to commute to work from Pakistan?

• What should our relationship be with the Taliban?

• What would this require? How many troops and other military resources at what cost and for how long?

Thoughtful and careful consideration of circumstances, goals and alternatives before committing to a course of action was supposed to be one of the hard lessons we learned in Vietnam more than 40 years ago, and again in Iraq six years ago. Absent clear and achievable policy objectives and a cold-eyed assessment of the costs to achieve them, the United States should not commit a single additional soldier, sailor, airman, or Marine to Afghanistan.

Before a decision is made, Obama, after proper consultation with Congress and with the support of the American people, must be able to articulate a compelling case with "clear and achievable objectives" for a continuing U.S. commitment in Afghanistan.