Michael Sherwin teaches social studies at a well-regarded public high school in Corvallis, Ore. When the pandemic hit, he was told he had to follow controversial new rules being adopted throughout the country. Among them was that student work could not be graded less than 50 percent.

At a meeting with district leaders, he and other teachers objected. The rules destroyed important incentives for learning, they said. The response from the leaders at the time, Sherwin said, was: "Thanks for your input. No change."

Sherwin, who has been teaching for 40 years, reluctantly obeyed, and was happy when the 50 percent rule was dropped a year ago. Other teachers around the country told the Post they have disregarded some of the directives, which still exist in many schools, but have opted to keep that quiet. They could send angry letters to the superintendent. They could protest at school board meetings. But who has time for that?

Much is going on at schools these days that people are not hearing about. A national effort to foster equity by easing grading and assignments that might frustrate students has become what could be the most divisive educational issue in the country. It has sparked much more concern among teachers than heavily publicized debates over race and sex lessons. But the unrest over grading has remained relatively quiet because those involved don't think going public will do them much good.

Parents often don't understand the new rules or are just grateful for less of the homework that can spoil a family's evening. Above-average students do what is necessary to qualify for good colleges and take independently written and graded Advanced Placement or International Baccalaureate exams that don't have 50-percent rules. Mediocre students are happy to get passing grades for little work. Many administrators and legislators like easier grading because it raises graduation rates, which are becoming the major measure of high schools as support for standardized testing fades.

Teachers with tenure have advantages in this underground struggle. A science teacher in Illinois who is also resisting the reforms said, "When teachers aren't tenured, they have to have [gumption] to say no to a principal. Once you have tenure, the onus is on the principal to prove that you are a bad teacher."

Rebel teachers are often supported by department heads, usually teachers or former teachers themselves, who help cover up the rule-breaking.

Some teachers are willing to complain to the Post, but many don't want their names used. "When students are not taught about negative consequences, then they never learn how to come back from a bad grade, or the value of sticking with something that is hard and really working through it," said a teacher at Wootton High School in Montgomery County, Md. While his district "continues to do everything they can to make things easier on kids, they also continue to not give a whit about teachers."

Brian Donlon, a social studies teacher in Montgomery County, said "I have kids who have barely come to class and turned nothing in but have 50 percent. [The rule] is one piece of the larger puzzle, to inflate grades and graduation rates so school system leaders can claim success." He said he is retiring in two years.

Montgomery County Public Schools spokesman Christopher Cram said, "Students can be assigned zero if there is no attempt to meet the basic requirements of the task or assignment or if the student engaged in academic dishonesty. This can only be the choice after appropriate support, intervention, and two-way communication with the student and parent." The flaw in that rule, Montgomery County teachers say, is that parents can and have saved their children from zeros by not responding to teachers' phone calls or emails.

A high school teacher in Las Vegas said, "Kids are working the system and there is nothing we can do about it." An English teacher in Indianapolis said, "I can tell you without hesitation that this rule threatens to destroy an entire generation." Sam Dixon, a teacher in Utah, said his state's system "doesn't teach students how to think critically, it doesn't teach students how to read, it doesn't teach students how to write, it simply teaches them systems for them to game."

A Maryland teacher said her high school students who are dually enrolled in courses at a local college "are like deer in the headlights. They do not understand ... why they got a zero for something they chose not to do." One D.C. teacher called the 50-percent rule "a security blanket that lifts everyone's grades and lets us all feel better about student achievement even if there isn't any real academic growth at all."

The Post could find no data on how many schools have the 50-percent rule, or have banned homework deadlines and other traditional assessment practices opposed by what is often called the standards-based grading movement. Both the implementation of the new rules, and the resistance to doing so, proceed unseen in classrooms, where investigators and other curious strangers are rarely found.

Some teachers accept the 50-percent rule as a long-needed correction to messy record-keeping. One veteran teacher in the D.C. schools called it "a hedge on teachers' inequitable grading practices ... using unexplainable point totals and shoddy feedback systems."

Some parents find the new rules a relief. A mother in Fairfax County, Va., said in a comment online that "many very involved and reasonable Fairfax parents really like this new grading system. It exponentially decreases the daily stress level."

A teacher in suburban Chicago said his school has whittled down some new rules. The 50-percent minimum grade was reduced to 40 percent for tests. Teachers are permitted to give a zero grade for homework at their own discretion. Corvallis superintendent Ryan Noss said his district dropped the 50-percent rule because of negative feedback from teachers.

Some parents have begun to investigate the new policies. Kim Putens, whose children recently graduated from West Potomac High in Fairfax County, sent me the school's grading rules, which she had carefully studied. Her children had top grades, took many AP courses and were among the group unaffected by the changes because their personal standards are so high.

Putens said she understands the reasons for the minimum grades but, "in my humble opinion, this is a lazy way of giving kids a leg up rather than doing the hard work of lifting up and educating students that need remediation or more help."

With the new rules producing little open debate, and with recalcitrant teachers able in some cases to stick with old ways they prefer, the result is likely to be confusion, resentment and insufficient learning. That will be bad for schools that the latest federal test results show need all the help they can get.