He leads off by quoting this article by WaPo contributor and English teacher Patrick Welsh. 

All parents want their children to be with the nice kids, the bright and well-behaved types who will pull classes up, rather than with kids who will drag them down. In big, economically and ethnically diverse high schools such as mine, T.C. Williams in Alexandria, Va., where there is enormous variation in academic abilities, average kids run the risk of ending up in one of two tracks: in classes full of students with weak skills and lousy attitudes or in so-called advanced courses where they find themselves in over their heads.

[snip]

What is happening more and more around the country is that average students are being pushed into Advanced Placement and International Baccalaureate classes to make schools appear as though they have high standards. In a sense, average kids have become a pawn of school boards and administrators who want to get good PR for boosting the numbers in supposedly rigorous courses. Administrators here in Northern Virginia boast about the numbers of kids taking AP courses but don't talk much about students' test scores.

However, Mathews goes on to point out that Wakefield High School, a demographically similar school just a few miles away from Welsh's school, has had an entirely different experience.  

You would think, if Pat is right and AP is too tough for the many average kids you find in schools like that, then Wakefield's AP success rate would be similar to T.C.'s. But it's not.

Wakefield, like the other Arlington schools, welcomes average students into AP and requires them to take the AP exams. In 2005 it gave 473 AP tests and had 233 graduating seniors, for a Challenge Index ratio of 2.0300, a participation rate 36 percent higher than T.C.'s. That means it likely had a much larger portion of average students taking AP courses and AP tests than T.C. did.

And yet its passing rate on the AP exams was 51 percent, higher than T.C.'s 39 percent.

Mathews then makes the obvious assertion: push the kids, and they'll achieve.  However, there's something even more disturbing at work here--namely, that AP doesn't mean what it used to:

In an American education system full of plans for better high schools, more and more courses have impressive labels, such as "honors," "advanced," "college prep" and "Advanced Placement." But many researchers and educators say the teaching often does not match the title.

"A company selling an orange-colored beverage under the label 'orange juice' can get in legal trouble if the beverage contains little or no actual juice," said a February report from the National Center for Educational Accountability, based in Austin. "But there are no consequences for giving credit for Algebra 2 to students who have learned little algebra."

Grade inflation is a well-known issue. Many critics of public schools contend that students nowadays get better grades for less achievement than they used to. Experts also worry about courses that promise mastery in a subject but fail to follow through. Call it course-label inflation.

Astute readers will note that it was Mathews himself who wrote this in his column from last week.  In this light, consider this quote from Walsh's new commentary:

What is happening more and more around the country is that average students are being pushed into Advanced Placement and International Baccalaureate classes to make schools appear as though they have high standards. In a sense, average kids have become a pawn of school boards and administrators who want to get good PR for boosting the numbers in supposedly rigorous courses. Administrators here in Northern Virginia boast about the numbers of kids taking AP courses but don't talk much about students' test scores.

What is needed is a middle track for average students — call it college-bound or some other name that will please parents. The fact is that every child can learn, but every child cannot learn as fast as, or learn as much as, every other child.

So connect the dots.  Even in the face of reports that AP standards are being watered down, Walsh still says that AP is just too much for some kids to handle.  

Consider an analogy from weightlifting.  Weightlifters push themselves right to the brink, to that thin edge between what they can do and what they can't.  Yes, that edge is different for everybody, but over time, an interesting thing happens: as the weightlifter keeps working at it, that upper limit keeps getting pushed up.  In other words, he can handle more, and as a result becomes stronger, which of course was the whole point all along.  And more importantly, if that edge isn't discovered, the weightlifter's goal won't be achieved. 

I don't question that there are some kids who don't learn as fast as or as much as others.  And some will take exception to my analogy, suggesting that we're after long-distance runners as opposed to weightlifters or, say, sprinters.  But Welsh seems to suggest that kids are being overloaded, pushed beyond what they can handle.  Mathews responds that, for many students, that upper limit is never even touched because many teachers don't take the time or effort to help them get there.  But given Mathews's prior column, I think the truth is even worse: given the present state of standards and expectations in which even advanced classes are being watered down--where kids are given 30-pound weights with 50-pound labels--even our AP kids think they're finding their present limits when in fact they're nowhere close to discovering them.  Which makes Welsh's line of reasoning a form of academic determinism that's even more dangerous, even more toxic, than Mathews suggests.

Walsh is accurate in his assertion that some students can't learn as fast or as much as others.  But it takes no effort to go from there to believing that a student's ability to learn is maxed out or static.  That's a notion I flatly reject.  And, come to think of it, so did Jaime Escalante.