George W Bush made the decision to send extra troops after nearly every advisor urged him to take other courses. It was his best, bravest and loneliest decision as President after he had stubbornly stuck with the failed Rumsfeld strategy for far too long.
Ultimately the surge was about proving commitment as Bush made clear one year after he had despatched more troops:
"One year ago, our enemies were succeeding in their efforts to plunge Iraq into chaos. So we reviewed our strategy and changed course. We launched a surge of American forces into Iraq. We gave our troops a new mission: Work with the Iraqi forces to protect the Iraqi people, pursue the enemy in its strongholds, and deny the terrorists sanctuary anywhere in the country. The Iraqi people quickly realized that something dramatic had happened. Those who had worried that America was preparing to abandon them instead saw tens of thousands of American forces flowing into their country. They saw our forces moving into neighborhoods, clearing out the terrorists, and staying behind to ensure the enemy did not return."
In the context of today's situation in Afghanistan some of those words are really worth repeating: "Those who had worried that America was preparing to abandon them instead saw tens of thousands of American forces flowing into their country."