In the last Republican presidential debate before the Jan. 3 Iowa caucuses, two of the candidates, Mike Huckabee of Arkansas and Mitt Romney of Massachusetts, argued about which had the better education record as his state’s governor.

You can read a transcript of the debate here, and you’ll see that education was a hot topic—from Congressman Ron Paul’s assertion that the major education problem is that judges have driven God out of schools to former New York City Mayor Rudy Giuliani’s repeated assertion that school choice will result in an education “revolution.”

But back to the issue of who’s the best governor on education...There are three candidates with gubernatorial experience in the field—besides former governors Huckabee and Romney, there’s current New Mexico Gov. Bill Richardson, a Democrat.

In reponse to a question today about education, Huckabee declared that he had the “most impressive education record.” He certainly has one of the longest ones—having served from 1996-2007 in Arkansas’ highest office, when he presided over tumultous debates about rural school consolidation and a school funding system that had been ruled unconstitutional by the Arkansas Supreme Court.

Romney retorted that he wasn’t so sure that Huckabee should make that claim—and boasted of high test scores while he was governor in Massachusetts from 2003-2007.

Coincidentally, about that same time Romney was answering that question, I was talking to the president of the Massachusetts Teachers Association about Romney for an upcoming story I’m working on for Education Week about the education records of the governors-turned-presidential-candidates. And although MTA President Anne Wass is a fierce opponent of Romney—who provoked the teachers’ unions at nearly every turn with talk of merit pay and possible budget cuts to some education programs—she made a worthy point. Massachusetts, a high-income, high socioeconomic status state, had high test scores before Romney took office, while Romney was in office, and continues to have high test scores now that he’s left office. (By the way, in the debate, Romney said the unions have been the “biggest obstacle” to education reform.)

But the larger question is, how much credit may a governor take—or how much blame should he get—for falling or rising test scores?