I find myself unmoved by the argument "if you have standarized tests we won't have time to teach anything but what's on the tests".
Standardized tests are not new. I took them in the 70s and early 80s: a few days of sitting in home room, filling out circles with a number two pencil. Big deal: they had no affect on my actual grade. What they were was a benchmark for the school.
As I understand it, what _is_ new is the pressure on the schools to produce kids who can pass the test.
Since there is now a great deal on the line for the district ( funding ), a lot more time is devoted to producing students who can pass the tests. This is only natural, and was easily seen as a consequence of no child left behind.
If such a dynamic did exist, one could predict it would take hold on a national level with the advent of NCLB. Then one would expect that NCLB had the effect primarily of making standardized tests less accurate...