I alluded to this in my debate sum-up below. But one of my big questions about this debate was Hillary Clinton's lack of aggressiveness toward Barack Obama. I think it spoke very well of her on a number of levels -- personally, as a potential leader, etc. She made her case on her merits and policies.

But there is no mistaking the fact that by every metric and every visible trendline Barack Obama is in the process of winning the nomination. At least conventional political logic would dictate that she had no choice but to go after him just as she has been doing on the campaign trail.

But she didn't.

Some are saying that she realizes she's losing and she wants to lose gracefully or not damage the interests of the Democratic party in the fall. Others that the tack she took is actually the best one for her to take. I suspect it's a bit of both.

But that was the big silence in this debate.