A year ago, the idea of setting national education standards was a lot like the idea of legalizing marijuana: Despite all common sense, it just wasn't going to happen. It didn't matter that No Child Left Behind proved that when states are allowed to define their own standards, most dumb them down. The thinking was that states' rights types would never agree to let the feds mandate what kids should learn about sexual health or evolution. Unions would resent any imposition on the autonomy of classroom teachers. Anti-testing advocates would decry the narrowing of curricula.

Yet on June 1, the National Governors' Association announced that 49 states and territories have signed on to an agreement, called the Common Core Standards Initiative, to develop national standards in math and English. For education reformers across the political spectrum who have long urged that the United States join its developed world peers in articulating national standards, the news is a major victory.

What changed? Secretary of Education Arne Duncan has made clear that in awarding stimulus money, his department will favor states with internationally benchmarked education standards. Republican social conservatives, who stymied Presidents George H.W. Bush and Bill Clinton when they tried to move toward national standards, are today a disorganized minority. And recent polls show that Americans are more anxious about layoffs than about sex ed. What's more, Randi Weingarten, the most influential national teachers' union leader, now vociferously supports national standards.

At this point, however, the initiative is vague, and its outcome uncertain. The state education departments have simply agreed to work together to develop the standards, not to actually implement them. And beneath the feel-good press releases announcing the initiative lie some real, unresolved policy differences among standards supporters, in part over testing.

The problem is that the initiative's co-signers aren't just state governments--they are also testing groups: Achieve, a nonprofit that advocates for more effective standardized tests; the College Board, maker of the SAT; and ACT, which administers a competing college-entrance exam. Right now, the College Board and ACT have little engagement with the K-12 education sector. They do, however, have ample experience creating and administering national exams. And there is little doubt that one goal of this national-standards process is to create standardized tests--not one single national test but perhaps two or three options from which states can choose.

As oligopolists, it makes total sense for the College Board and ACT to be eyeing, together, expansion into the immense K-12 assessment market. But given these testing companies' track records, it is worth asking if this is a wise idea. A number of studies have found SAT scores are far less effective than high school grades in predicting how well students will perform in college, and professors say standardized-test prep does little to teach students the research and critical thinking skills they will need at the college level. Because of these shortcomings, an increasing number of colleges--led by the giant University of California system--have made standardized test scores optional for admission.

There is no reason to assume that the overdue move toward federal standards must lead to national standardized tests administered by the college-admissions giants. In Finland, whose schools are ranked best in the world, there are detailed national curriculum guidelines but no mandated testing regime to go along with them. If past American efforts are any guideline, what we're likely to come up with is the exact opposite: vague standards and high-stakes tests. For example, 35 states participate in the Achieve-led American Diploma Project, in which states agreed to roughly align their education standards. Under that system, high school students are required to write a six- to 10-page research paper. In Finland, though, the national curriculum calls for research papers to be part of every subject course, from the life sciences to history and philosophy.

A major disadvantage of the states and testing giants leading the push toward national standards is that without Washington's involvement, the issue is less likely to register on the mainstream media's radar. But the public ought to be paying close attention. It would be a shame if national education reform further cemented a system in which passing standardized tests is the goal of learning. That would discourage creative teaching and push affluent families looking for more flexibility into the private system. And that simply isn't in the public's common interest.