Verified answer

ASk hillary and obama.

The United States has funded a group called Jabhat Al Nusra, which is Al Qaeda's affiliate in Syria. This support originated from their opposition to Bashar al Assad, when they (stupidly) essentially armed anyone who was willing to fight the Assad government of Syria in an attempt to satisfy Saudi Arabia (who also did this and still do on a much larger scale). One of these groups was Jabhat al Nusra.

Because it's politicians are a bunch of fools who never learn. The Reagan administration supported Bin Laden and his buddies in Afghanistan against the USSR and look what he did to us later.

that's not true.