In 2011 NATO, under the US leadership, disrupted Libya and therefore helped ISIS to get the influence there. Now, new bombing campaign is very probable. In reality it will only help ISIS, similarly as the USA are helping them in Syria.
International coalition acted with UN Security Council mandate (bit.ly/1kYkWWp), to protect civilians. Political instability after Gaddafi's fall, caused by lack of cooperation between rebel groups, led to fragmentation of the country and rise of extremist groups in some areas. There is no evidence of US support to Islamic state. USA lead the coalition fighting Islamic state in Syria.