What chance is there of truly intelligent life evolving on Earth?

I define IL as a form that is ingenious, imaginative, creative, but smart enough not to shoot itself in the foot (or head), or destroy what it needs for a satisfying life, with its own "cleverness". Obviously we're not there yet while we search for it in space - but there have always been isolated hopeful signs? So what are the odds? And what might we do to help?