That's why D.C. Schools Chancellor Michelle A. Rhee should be supported for taking the difficult but necessary steps to rid the system of ineffective teachers.

In a move seen as unprecedented in the nation, Ms. Rhee announced Friday that 241 teachers -- roughly 6 percent of the teaching force -- are being terminated because of poor performance and licensing issues. An additional 737 have been rated minimally effective, will not be eligible for step increases and have one year to improve their performance or face dismissal. That means that the system could see nearly a quarter of its teachers dismissed within two years, a prospect Ms. Rhee called "daunting." Nonetheless, she is right to argue that "every child in a District of Columbia public school has a right to a highly effective teacher -- in every classroom, of every school, of every neighborhood, of every ward . . . ."