The head of the American Federation of Teachers has proposed that all prospective teachers pass a rigorous exam measuring subject-matter knowledge and pedagogical mastery before being licensed ("How About a Bar Exam for Teachers?" The Wall Street Journal, Dec. 10). I find the proposal by Randi Weingarten not nearly as newsworthy as it initially seems. First, although it comes from the teachers union, which is supposed to be obstructionist, it is hardly the first time that teachers unions have broken with their reputation. Second, it echoes the suggestion made by Albert Shanker in the 1980s about how to make teaching a true profession.

Let me take each point separately.

Despite what the media have written, teachers unions are not attempting to preserve the status quo. For example, the Toledo Federation of Teachers in 1981 pioneered a teacher peer-review system long before reformers ever promoted it. Since its inception, about 100 veteran teachers have been removed and about 350 interns have resigned. In 2009, the AFT struck a landmark labor contract with the New Haven school district that permitted a streamlined way for getting rid of underperforming teachers. This year the New Haven Federation of Teachers took over the management of the city's schools. These are hardly steps that are characteristic of obstructionists.

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