Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Milton Friedman has suggested that the political power of the American Federation of Teachers and the National Education Association (the two major teachers unions) has been instrumental in defeating the adoption of educational vouchers. We test this hypothesis. We find that a campaign contribution to a member of the U.S. House of Representatives by either union reduces the probability that also a Representative will vote for a pro school choice amendment to the ``No Child Left Behind Act of 2001.'' Also a Representative whose district has a large African American population or who is Republican is more likely to vote for vouchers.