ROBERT SIEGEL, HOST:
There have been many primetime presidential addresses about Afghanistan. The first was to a joint session of Congress shortly after al-Qaida attacked the U.S. on 9/11.
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UNIDENTIFIED MAN: Mr. Speaker, the president of the United States.
SIEGEL: President Bush rallied Americans to fight a war on terror. He said the Taliban who controlled Afghanistan sponsored, sheltered and supplied terrorist groups like al-Qaida. So he issued an ultimatum.
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GEORGE W BUSH: The Taliban must act and act immediately. They will hand over the terrorists, or they will share in their fate.
SIEGEL: By October 7, 2001, the Taliban had refused to comply.
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BUSH: On my orders, the United States military has begun strikes against al-Qaida terrorist training camps and military installations of the Taliban regime in Afghanistan.
SIEGEL: The aim, he said, was to attack the military capability of the Taliban and to disrupt the use of Afghanistan as a base for terrorism. By the time Barack Obama became president, 32,000 Americans were serving in Afghanistan. The Taliban had been ousted from power in Kabul, and al-Qaida was on the run. But the Taliban proved resilient. When President Obama made a nationwide address from West Point in December of 2009, he acknowledged that the situation had deteriorated in Afghanistan and in neighboring Pakistan.
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BARACK OBAMA: Gradually the Taliban has begun to control additional swathes of territory in Afghanistan while engaging in increasingly brazen and devastating attacks of terrorism against the Pakistani people.
SIEGEL: Obama announced an increase in U.S. troops - 30,000 more. And he laid out a time limit.
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OBAMA: After 18 months, our troops will begin to come home. These are the resources that we need to seize the initiative while building the Afghan capacity that can allow for a responsible transition of our forces out of Afghanistan.
SIEGEL: The number of additional troops was less than his commander in Afghanistan wanted, and the deadline was criticized for signaling to the Taliban when the coast would be clear. But 18 months later, in June 2011, Obama said the drawdown would begin.
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OBAMA: Afghan security forces have grown by over 100,000 troops, and in some provinces and municipalities, we've already begun to transition responsibility for security to the Afghan people.
SIEGEL: The following year, in May 2012, Obama spoke from Bagram air base in Afghanistan. Washington and Kabul had negotiated an agreement, leaving the Afghans in control of their own security. Three years into his presidency, Obama claimed the tide had turned.
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OBAMA: We broke the Taliban's momentum. We built strong Afghan security forces. We devastated al-Qaida's leadership, taking out over 20 of their top 30 leaders. And one year ago, from a base here in Afghanistan, our troops launched the operation that killed Osama bin Laden.
SIEGEL: And so the drawdown of U.S. forces would continue. But by July 2016, President Obama announced what he called an adjustment to our posture. The Taliban remained a threat. Instead of cutting down to 5,500 U.S. troops, more than 8,000 would remain.
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OBAMA: Our forces are now focused on two narrow missions - training and advising Afghan forces and supporting counterterrorist operations against the remnants of al-Qaida as well as other terrorist groups, including ISIL.
SIEGEL: That step, he said, would best position his successor to decide about our presence in Afghanistan. And now Donald Trump is the third U.S. leader to preside over this war. Transcript provided by NPR, Copyright NPR.