jingle On the one hand you say it was a mistake getting rid of Saddam Hussein and yet you wanted the US/UK to get rid of Assad.
As I understand it, ISIS is a combination of Syrian and Iraqi rebels. On 15 February, Time magazine reported:
"Arab backers of the Syrian opposition are stepping up their military support for the rebels, providing the beleaguered forces with more sophisticated anti-aircraft weaponry in the wake of a second round of inconclusive talks with the Syrian regime.
The Wall Street Journal, citing an unnamed Arab diplomat and opposition sources, said that Saudi Arabia would give the Syrian opposition Chinese man-portable air defense systems, or Manpads, and antitank guided missiles from Russia. The U.S. has opposed that kind of military support out of fear that the weapons could fall into the hands of terrorists or al-Qaeda affiliates.
The new aid is being delivered directly to the more moderate Free Syrian Army in the south of Syria, which has been launching an offensive against government forces since January. Meanwhile, the U.S. has increased its financial support of the rebels, paying million of dollars for the fighters’ salaries."
So it appears that the original arming of the rebels came from the US's close ally, Saudi Arabia, and, despite worries about such assistance falling into the wrong hands, substantial funding was provided by the US in an attempt to defeat Assad. It seems that providing weapons and money to "carefully selected" rebel groups (as the article described them - not quite sure what criteria for selection they used) was probably not a good idea.