Why is the US backing troops fighting alongside al Qaeda? This seems ominous - and stupid: Syrian rebels spearheaded by al Qaida in Iraq and its local allies took control Tuesday of a crucial military airport in northern Syria, opening a vital supply line between the rebel-held north and Turkey. The end of the siege that had clamped down the airport since last October began Monday, when two non-Syrian nationals drove an armored personnel carrier, loaded with explosives, into a position manned by defenders of the regime of President Bashar Assad. The explosion devastated the Assad troops and allowed rebels to overrun the Mannagh Air Base in Idlib province. Those rebels included multiple units affiliated with the Syrian Military Council, an umbrella group with U.S. backing. That poses an uncomfortable pairing of a group supported by U.S. resources with Islamist organizations Washington has labeled as terrorist.