It isn’t being easy being a teacher these days. Over the past three years, hundreds of thousands of public school teachers have lost their jobs nationally; the exact number is hard to pin down, but it’s large -- and probably unprecedented since public school became compulsory.

But, as most teachers would tell you, it isn’t just job security that worries them, but an unusually hostile attitude even among people who, two decades ago, would have been strong supporters of public education.

One of the little-noticed policy continuities between the Bush and Obama administrations is their approach to public education. Both emphasize standardized tests, criticism of traditional public schools, and a strong emphasis on firing teachers and closing schools as paths to improvement. These approaches were embodied in the No Child Left Behind bill passed by bipartisan majorities in 2001.

Unfortunately, there’s little evidence these techniques actually improve education and student performance, and much evidence that it harms them. Ditto for the idea that charter school will revolutionize education; comprehensive studies show no difference in outcome between charters and the standard model.

What drives all these education reform efforts is the touching but equally faulty idea that there’s a magic bullet that will dramatically improve schools and provide every student with mastery of the curriculum and top-notch job skills. Education is a slow, often painful, lifelong process. One of the best things we could do for public schools and our kids is to keep expectations modest.

Last Monday, a Harvard University study was released analyzing results of the National Assessment of Educational Progress, perhaps the nation’s oldest and most consistent measure of student achievement. The news is mixed: Maine still ranks 12th among states in achievement, but its scores have barely changed in 20 years while most other states have made more progress, causing Maine to drop from 3rd to 12th in the rankings.

The results were not mixed to Gov. Paul LePage, who pronounced them “pathetic,” a word he really ought to use more sparingly. Education Commissioner Stephen Bowen was more measured, calling the Harvard report “disappointing,” and consistent with other recent reports. Bowen, despite his tenure at the Maine Heritage Policy Center, seems to approach education more from a policy than an ideological position, and perhaps – over time – he can convince the governor to tone it down.

For LePage then went on to pronounce that Maine’s previous investments in public school were useless, because they didn’t pay off in achievement gains. He didn’t read the Harvard report, evidently.

While the report did say that Maine – along with West Virginia and New Mexico – saw few gains from higher spending, a larger number of states – Colorado, Florida, Michigan, Indiana, Idaho, and North Carolina – did see significant results.

The appropriate conclusion is that spending is important, but not the only factor. Few would argue that run-down schools and poorly paid teachers are consistent with high-quality education.

LePage isn’t wrong about education reform, though. Many of the institutional players have been resistant to change and experimentation. Groups representing superintendents, school boards and principals barely figure in the public debate.

And former Gov. John Baldacci’s blueprint for school consolidation relied heavily on coercing local school districts to join together, and had limited success as a result.

If LePage wants to help schools become more efficient with tax dollars, he might revisit the topic with a cooperative approach. It’s difficult to see how Maine can support the number of schools it has now, let alone significantly expand them with charter schools.

Teacher evaluations – the other significant reform bill enacted this year – may help long-term, but we should again be cautious with expectations. The idea that schools are plagued by lousy teachers immune from firing is a fantasy. Teaching is demanding work – try standing in front of 25 students and just maintaining order – and most poor teachers leave on their own.

Finally, we can’t be honest about public education without acknowledging the strong link between low achievement and poverty, which actually explains much of the gap between the U.S. and other developed nations.

Children who are poor start behind their peers and learn at dramatically lower rates. With child poverty exceeding 25 percent in Maine and the nation –- higher than it’s been for 50 years –- this is a sobering reality. It doesn’t mean poor children can’t excel, but it should prompt us to reconsider the rising inequality that’s such a prominent feature of 21st century America.

Perhaps we should adopt the Hippocratic oath in our approach to education: First, do no harm.