The United States of America does not negotiate with terrorists (individuals or states); at least not the kind that plot and carry out terrorist attacks in U.S. cities, hijack airplanes, or that hold hostages and make unacceptable demands. It does negotiate with its enemies on the battlefield; and President Hamid Karzai’s announcement Saturday that Afghanistan and the United States are engaged in peace talks with the Taliban is a smart move, with the right carrots and sticks.

We can split hairs over the definition of a terrorist and the differences between an international terrorist organization like al-Qaeda and a deposed Islamist militia group like the Taliban that ruled large parts of Afghanistan from 1996 to December 2001. What’s most important when it comes to who we should or shouldn’t negotiate with, however, isn’t who or what they are but what we are negotiating for.

We don’t negotiate with terrorists that demand quid pro quos or make outrageous demands that if given in to would only encourage more of the same. Negotiating to end a war and over the future of an country, however, is quite a different matter.

Only a political solution can bring about the long-term stability of Afghanistan, and we can’t achieve a political solution without negotiation. The complete defeat or unconditional surrender of the Taliban is not achievable with the forces or resources we have been willing or can afford to dedicate to the war effort.

Furthermore, given Afghanistan’s tribal culture, the opium trade, and the weakness and corruption of the Karzai government, it will take decades to achieve the nation building necessary for long term stability in Afghanistan. Neither the International Security Assistance Force nor the Afghan National Army can sustain a war with the Taliban that long. U.S. forces already have been at war there for ten years, and Americans are ready for them to come home.

Negotiating a peace settlement in which the Taliban cease hostilities, buys in to an elected national government in Kabul, and are given a measure of autonomy in tribal regions that they control could lead to a long-term political solution. However, it would have to involve right incentives and disincentives that would prevent it from falling apart after the bulk of U.S. forces leave; and it would have to allow for the indefinite presences of U.S. advisors in Afghanistan.

What we must avoid is another peace agreement like the 1973 Paris Peace Accords that ended the fighting in Vietnam but ultimately led to the fall of Saigon, the overthrow of the South Vietnamese government, and the humiliating defeat of the United States in 1975. Circumstances surrounding the Vietnam War were different. The Taliban aren’t the Viet Cong or the North Vietnamese, anti-war protests aren’t tearing America apart, and the U.S. Congress isn’t about to cut off funds to fight the war—not yet anyway. There are important similarities, however, and we should not make the same mistakes in addressing them.

Like the North Vietnamese Communists and the Viet Cong, the Taliban are ideologically driven. The Taliban aren’t nationalists like the Vietnamese were nationalists, seeking the restoration of a long established nation and central government; but they seek to rule under the ideology of Islam as the Vietnamese sought to rule under the ideology of communism. In both ideologies the United States is is an existential threat.

Like the Vietnamese Communists, the Taliban’s ideological imperative would drive them to look for the first opportunity to abrogate peace accords and topple the ‘American crony government’ in Kabul. Therefore, even substantial subsidies and assistance to supplant income from the opium trade and regional autonomy would be insufficient to dissuade them from doing that.

President Richard Nixon effectively used the bombing of North Vietnam and rapprochement with the Soviet Union and China to bring the North Vietnamese to the negotiating table. Once the agreement was inked, however, Congress and the American people gave him no leverage to enforce Vietnamese-Communist compliance with the peace accords after they were signed.

We must back up whatever peace agreement we negotiate with credible disincentives for abrogating its provisions. Taliban leaders have to know that once U.S. combat forces have withdrawn from Afghanistan, we will act quickly and lethally against those who threaten the elected government. They have to lie awake at night contemplating whether a pilot behind a console at a U.S. Air Force base in Nevada has their bedroom window in a drone-sensor’s crosshairs or if a U.S. Navy SEAL teem is hovering in a stealth helicopter above their compound.

The North Vietnamese and the Viet Cong understood that American public opinion was easily manipulated and that Americans had short memories. They knew they couldn't defeat us on the battlefield, so they targeted our endurance. More than three million people were slaughtered in Indochina in the years following the Vietnam War while Americans looked the other way. Afghans need not look back that far. Americans quickly turned their backs on Afghanistan after the withdrawal of Soviet Forces in 1989.

All successful peace negotiations require both perceived mutual benefit and disincentives for either side to take advantage of peace to prepare for war. The Taliban have their redoubts in the mountainous Afghan-Pakistan border region and their supporters in Pakistan’s Inter-Services Intelligence organization. They will most certainly take advantage of this to prepare for future war unless the cost of doing so outweighs the benefits.

If Washington can work out the terms of an agreement that the Taliban, it’s supporters in Pakistan, the Karzai government, and the United States all perceive holds benefits for them, and the U.S. can maintain sufficient and lethal disincentives for abrogating that agreement, we should do our best to negotiate it.

Finally, we must not allow the coming U.S. presidential election to undercut a lasting negotiated peace settlement. Both President Barack Obama and his Republican challengers will be under great pressure to placate the majority of American voters who have soured on the war in Afghanistan. Any peace agreement that fails to hold Taliban leaders feet to the fire over the long term, however, will only guarantee that it will fail.