Al-Qaida and its allies have triumphed precisely because of a lack of foreign intervention and support, not in spite of it. When the FSA was first formed in the summer of 2011 under the leadership of Riad Assad it was made up of relatively moderate officers and supported by an average cross-section of Syrian society.
Had the United States chosen to intervene then, by creating an intelligence network (which many have intimated still does not exist) and controlling the arms conduits to Syrian groups, it would have been in a position to choose the "winners" of the Syrian opposition.
By empowering legitimate or moderate groups and organizations with the firepower to achieve results, it would have removed the space for al-Qaida to operate. Instead, by holding back the flow of arms and support, the United States created the environment for al-Qaida to flourish.
It is a recurring theme in recent history. While the Libyan Civil War was raging observers and insiders noted the increased presence of Islamist groups, potentially even al-Qaida, among the opposition. This was cited as part of the reason why intervention should be avoided.
However once intervention commenced it reduced the need for the opposition to rely on al- Qaida volunteers, and gave them a reason to make themselves more amenable to their new Western allies.
However, many conflicts go the route of Chechnya, with resolution taking so long that radical groups find a permanent presence, eventually supplanting or absorbing the original opposition.
That final point is what should concern Washington.
There is a definite expiration date on involvement. The longer the US waits, the more popular and powerful alternatives like al- Qaida will become. At some point, as this conflict rages on they will become a permanent fixture in the political mix, and perhaps even become the resistance itself.
Many now agree that Bashar Assad is likely to fall, one way or another. Whether or not it is the Syrian tricolor or the black flag of al-Qaida that is rung up in Damascus, is in fact entirely up to the United States.