When President Barack Obama took office in January, he inherited a drifting and under-resourced war in Afghanistan, being fought with roughly 35,000 U.S. troops.

Obama ordered 21,000 additional troops in March and then 30,000 more in December.

In a little over a year, he will have nearly tripled their numbers, taking ownership of what he calls "the war we must win."

And although his administration took three months to review Gen. Stanley McChrystal’s request for more forces, drawing criticism from the GOP that he was "dithering," every step the president has taken represents an escalation of the war, now in its ninth year.

In May, Obama sacked Gen. David McKiernan, the commander of all U.S. and international forces in Afghanistan, replacing him with McChrystal, a career special operations soldier who led the effort to track down and kill al-Qaida-in-Iraq leader Abu Musab al-Zarqawi in 2006.

McChrystal took command June 15. Alarmed by rising civilian casualties, he soon issued tough new rules that restricted the use of airstrikes and other lethal force. He followed that in July with a new counterinsurgency strategy that shifted the focus from killing Taliban fighters to protecting civilians.

But U.S. and allied casualties rose during the summer to their highest levels ever. At least 70 Western soldiers died each month from July through October, virtually double the rate of the previous summer. In the past year, nearly 500 foreign troops have lost their lives in Afghanistan, including more than 300 Americans.

On Aug. 30, McChrystal delivered a long-awaited assessment to the White House. It warned that without more forces, the mission would "likely result in failure."

He presented three options, with troop increases ranging from 10,000 to 80,000, and a corresponding risk, according to media reports.

By the time the new U.S. forces are fully deployed next May, there will be nearly 100,000 U.S. troops in Afghanistan. NATO countries have pledged an additional 7,000 soldiers; the total number of foreign troops in the country will reach nearly 150,000.

Their mission will be to secure Kabul, Kandahar and other key cities, while trying to turn the tide against the Taliban in the south and the east. U.S. and other Western officials hope the increase will also buy time to build up the Afghan security forces.

Obama says that the U.S. surge will last for 18 months, after which security responsibilities will be increasingly turned over to Afghan forces and U.S. troops will start coming home.

In laying out the ambitious agenda, the president has essentially bet that the war in Afghanistan will be either won or lost within the next year and a half. And whichever way it goes, 2009 will likely be regarded by history as the beginning of the end of our long involvement there.

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