Intent is only a fraction of what we use to judge action in criminal law. Action and result bear much more weight.
That would depend on the offense. As you so quaintly pointed out, the mens rea would be the key element in an attempted murder charge. You would have to make the case that the accused was "of the mind" to take another's life.
For an attempted murder charge to be successful does there really need to be an "actual attempt"? Or is simply planning and taking action toward that end sufficient?