Wonder no more, courtesy of Zerohedge:
"Two weeks ago, courtesy of the investigative work of Nafeez Ahmed whose deep dig through a recently declassified and formertly Pentagon documents released earlier by Judicial Watch FOIA, we learned that Western governments deliberately allied with al-Qaeda and other Islamist extremist groups to topple Syrian dictator Bashir al-Assad. In his words: "According to the newly declassified US document, the Pentagon foresaw the likely rise of the ‘Islamic State’ as a direct consequence of the strategy, but described this outcome as a strategic opportunity to “isolate the Syrian regime.”
Now, in a follow up piece to his stunning original investigative report titled "Secret Pentagon report reveals West saw ISIS as strategic asset Anti-ISIS coalition knowingly sponsored violent extremists to ‘isolate’ Assad, rollback ‘Shia expansion", Nafeez Ahmed reveals that according to leading American and British intelligence experts, the previously declassified Pentagon report confirms that the West accelerated support to extremist rebels in Syria, despite knowing full well the strategy would pave the way for the emergence of the ‘Islamic State’ (ISIS)."
Now we know!