Al-Nusra was the Syrian Jihadist group formed by Abu Al-Julani in the Syrian civil War.
They were definitely given money by America & Israel because they positioned themselves as only an Anti-Assad group & that they would fight against Hezbollah & any Shia group in the region, which is the case for basically all Salafist groups. After they lost Aleppo, Idlib & Bosra, they split as an organization & tried to join up with Al-Qaeda to help take back territory in the North.
They’re not an ISIL organization though, they’re actually completely different & have fought against ISIL in several offensives throughout the Syrian Civil War. If you wanna say they were funded & armed by the US, then you’d have an argument for Al-Nusra, but Al-Nusra is not ISIL, they’re actually enemies & ideologically different.
The US has a long illustrious history of funding & arming “rebels” who then in turn become terrorists organizations that we end up fighting against, that’s basically been our Foreign policy for the last half a century or so, I don’t deny that one bit. It’s been the one of the dumbest & most dastardly methods we’ve used that has pretty much backfired at every juncture.
However, that’s not the case for ISIS/ISIL, the US didn’t create those organizations & did not fund them, they did a poor job in understanding the phenomenon of the threat & how the role of the Iraq War essentially created a vacuum that allowed for the permeation of these festering groups to centralize on one battlefield, but they didn’t create the movement within itself.
ISIS/ISIL are zero-sum ideological groups that have no real life tangible goals that can be negotiated with, they literally want to bring about the battle of Malhama, that’s their only goal. The US doesn’t work with groups like that because they can’t be bought or sold, there’s no win in the loss there. They’re group that doesn’t want anything except destruction & you can’t manipulate a group like that to do your bidding. That’s why the US has never sat down with ISIS like they have with the Taliban & Al-Qaeda, because those groups are Sociopolitical organizations with religious proclivities, while ISIS/ISIL is a Socio-religious organization with no interest in politics at all.