Is God necessary for morality?

There is a very good debate between Prof. Shelly Kagan and Dr. William Lane Craig about "Is God necessary for morality?"

Find it here.

If I were to simplify the two sides, I'd draw parallels between the debate and different parenting styles (Parent == God). On one hand there are parents who tell their kids to behave in a specific way, follow certain rules; not because it is right (which it may or may not be; or it is right, because someone says so) but because the parent commands them so. Alternatively, the parent may reason with the child as to "why" certain things are morally objectionable (in the sense that they may face the consequences if others around behaved in the same way in future). Note the If here. There is no guarantee that immoral actions will be punished either directly or indirectly. It's just a matter of principle not to indulge in them.

It seems to me that for some kids strategy1 might work better ("do it because I say so") at least initially. Kids may fear the punishment by the parent. But in the long term, I think, strategy2 will help because it provides a proper justification, even though it is probabilistic. I agree that this analogy is not perfect in the sense that those arguing for God, say that s/he is omnipresent and omniscient and can punish you, even after you die.

Another parallel can be drawn with criminalizing non-voting in public elections. I think many people will agree that people should not be punished for not voting, but at the same time, it would be better if they voted. From the point of view of a "non" voter, his/her vote wouldn't change election results, which is mathematically true in most elections. But when viewed collectively, it will be disastrous for the democracy if everyone were apathetic towards elections.

I think each of us has an inbuilt conscience that helps us know what is right and what is wrong. So, in my opinion, belief in God is not necessary for morality. But it certainly helps us. In this case, the results matter more than the means.

Further discussion on this debate:
http://commonsenseatheism.com/?p=1810
http://www.reasonablefaith.org/contemporary-moral-arguments