Thomas makes an excellent point:

"I am convinced that the problem does not stem uniquely
from reduced spending on education.  Television
culture has something to do with it.  Though I will
admit to not having in-depth knowledge of the subject,
it occurs to me that the various attempts to "increase
student self-esteem" through such measures as easing
the SAT standards, etc, are indeed VERY STUPID."

Frank Furedi has a new book out, 'Where Have All The Intellectuals 
Gone?'  The book is terrible, but the good point that it makes is 
that 'dumbing down' is not about stupid people (not even stupid Americans), but about an elite response to popular disengagement with 
traditional collective institutions - politics, religion etc.  An element of the elite drew the conclusion that people were disengaged because culture and politics is just too sophisticated for the masses. They have pursued a policy of levelling down.  

As Thomas suggests, this will inevitably have a negative effect on people's achievements.  But it's important not to over-state this. People will rise above what's on offer.  

I think that the challenge for the left is to resist this, first by 
rejecting the idea that people are stupid, and second by raising the 
cultural standard.  Notwithstanding media oligarchs, public discourse is relatively open to people who say the same thing loudly enough and 
often enough, whether they're of the left or right.  If we're going to 
change the world we will need first to interpret it in a more sophisticated way.  The hard thing is not to be heard or noticed, but 
to inspire people to want to really engage with ideas.  And they, I 
think, will be the ones who will act on them.

On the subject of stupid Americans, Carl writes:
"(BTW, I note that in a subsequent post Carrol has anathematized this 
thread as "a stupid conversation, unworthy of anyone who has the remotest pretensions to left politics."  So I think it wise to absent myself from further involvement in this topic and go stand in the corner for a while.)"
I think this is a good idea for anyone tempted to continue that discussion.

James Greenstein