If this world campaign is going to be led by the same nutcases that created the mess in the first place one thing is for absolutely 100% sure: We´ll end up with an even worse mess.
That's true. If the Americans launch an all out attack against the ISIS, it will be viewed in the Muslim world as an American war against Islam, and the radical Islamists all over the world would travel to Iraq and Syria, to fight against the American troops. The fight will lag on for months, or even years, with no one really winning.