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Charles Krauthammer says that President Obama's foreign policy will not be remembered for the Iran deal or the death of Usama bin Laden, but for its disastrous failure in Syria.

The Obama administration is on the defensive over its Syria policy, as the city of Aleppo falls to Syrian President Bashar Assad’s government and civilians are evacuated.

The fall of the rebel-held city was preceded by desperate pleas from battered residents and reports of atrocities against them.

"Aleppo is his legacy," Krauthammer said on "Special Report" tonight. "History will remember this as kind of the symbolism of the whole policy of retreat and the inevitable outcome."

He explained that Obama failed to act when Assad crossed the "red line," and he failed to act when Russia began intervening in Syria on Assad's behalf.

Krauthammer slammed Obama's policy of "passivity" in the face of such aggression, allowing a humanitarian disaster to take place.

"And we see the result now."

Watch more above, and let us know what you think in the comments.

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