For the last couple of decades, politicians have been pretty regularly bashing public education and classroom teachers. What follows is a small antidote to that steady stream of criticism.

At the start of the school year, Ken Zieska was back at Cooper High, preparing to be a volunteer at the Robbinsdale school from which he graduated in 1969.

Zieska, retired from business and a career as an officer in the National Guard, spotted a plaque on the wall honoring a former history teacher of his, Mark Welter.

"I'd like to say hi to him," Zieska told the volunteer coordinator. "Do you suppose I could have his email address?"

Zieska was given the address and wrote his old teacher a note, thanking him for a memorable class.

"Good to hear from you," Welter responded. He said that he was honored that Zieska remembered him but "can't say I remember you."

That he couldn't remember Zieska isn't too surprising. Over his career, the 77-year-old Welter, who now teaches history courses to seniors as a volunteer at a program offered by the University of Minnesota, figures he's taught more than 20,000 students.

The student and the old teacher eventually got together, the student saying that he'd applied the lessons of the world course - from the big bang to the present - to many facets of his life.

Welter taught world history around 12 concepts. A quick summary:

1. Has any civilization been permanently successful?

 2. Does history offer evidence for a "superior" race, creed or culture?

 3. What is the impact of technology on culture?

4. How much unity is needed to have a culture function well?

5. Has anything in history happened because of one cause?

6. What is the best approach to change (revolution or gradual)?

7. Have there always been two logical views in addressing problems?

8. How important is a group's emphasis on learning?

9. To what extent do poverty and lack of opportunity lead to "isms"?

10. Are there general similarities between past and present?

11. To what extent do geography, topography and climate shape values and social structures?

12.  To what extent do cultural values and historical eras influence art styles and subjects?

"In business and in the military, I'd think about how nothing that happens is isolated," Zieska recalled. "What happens on a factory floor is not an island."

 When Zieska learned that Welter still was teaching the world history course, now to old folks instead of adolescents, Zieska retook the course to help him with his volunteer work at Cooper.

"What I remembered about his course was the enthusiasm he had," said Zieska. "It was a high-energy class."

More than four decades later, Welter has the same enthusiasm. The biggest problem Zieska had in retaking the course, it turned out, was working out how to address his teacher. He kept calling Welter "Mr. Welter."

"Would you please call me 'Mark,' " Welter said.

"Yes, sir," he responded.

Zieska has tried to apply the lessons of Welter in his volunteer work at Cooper, which is a different place from the one when he graduated. He volunteered because Zieska is one of those "make a difference" people.

You can, he figures, sit in the stands and complain, or you can get involved.

He's involved at a place that's very different from when he was there as a student. Four decades ago, the school was filled with virtually all-white, middle-class students. Now the halls are filled with diversity - racial (Latins, Africans, Asians, African-Americans) and economic.

The challenges facing teachers, Zieska says, are far greater from when he was a student. There are language issues. Students are "over-stimulated" by the technology all around them. But the vast majority of teachers he has seen as a four-hour-a-week volunteer seem to relish the challenge, Zieska said. What he has seen is a far cry from the drumbeat of political and news stories about bad teachers.

"I don't doubt that there are teachers who have burned out," Zieska said. "You see that in any company, in any profession. And I think it's too bad that there aren't ways for mid-career professionals to come into teaching without having to go through all the hoops."

Overall, though, he says, he sees the same sort of enthusiasm among teachers that his old history teacher showed then.

Welter despises the criticism teachers have been taking, and he abhors the emphasis on testing that politicians have created.

"Memorize, regurgitate," he said with contempt. "All the emphasis on math and science. ... Remembering is not learning. A change in behavior is learning."

The pols - and media - are pushing "left-brain"methods, Welter says. He is a "right-brain" (creative) guy.

The old teacher and his former student were at Cooper recently, talking together about all matter of things: education, politics and, of course, the oil spill in the Gulf of Mexico.

"This all started with Reagan," said Welter of the spill. "He's the guy who said, 'Get government off my back.' "

Zieska had a quick response.

"I have to say, 'I learned once there's no single cause for anything that happens.' "

The old teacher laughed. That's Concept 5. His student had learned well.