On Monday, the Dublin city school system announced it had removed art teacher Nancy Perry from her middle school classroom. She will retire at the end of the school year.

Two months earlier, the teacher had informed one of her students, a 13-year-old black youth, that President Barack Obama was no Christian, and neither was anyone who supported him.

Perry’s husband Bill sat in at the resulting parent-teacher conference. Bill Perry is a member of the Dublin school board.

“She presented to the parents a packet of several pages from a website that expressed her views on religion and politics. She was supported in this by her husband,” the local NAACP chapter reported.

Nancy Perry has apologized, according to a local newspaper account. Her husband has not.

It is possible to write this incident off as the result of racial dynamics in a small, southeast Georgia town. The Perrys are white. Eighty-six percent of the 2,500 students in Dublin’s schools are black – as is that fellow in the White House.

But if you are Alan Abramowitz and Steven Webster, the Dublin episode is evidence of a much larger and more troubling turn in American politics.

The two Emory University political scientists have just published a paper undergirding what you have long suspected — that politics has become a much meaner game over the last 30 or 40 years.

Abramowitz and Webster have found a way to measure that meanness, and even landed on a new name for it: “Negative partisanship.”

We were once strong believers in the concept of loyal opposition – a phrase borrowed from the British, based on the assumption that good intentions could be found on either side of the aisle.

“It used to be that presidents could attract support from the opposite party,” Abramowitz said in an interview.

But no more – and the change applies to both Democrats and Republicans. “In 1980, 55 percent of voters gave the opposing party a neutral or positive rating,” Abramowitz and Webster write. Twenty-seven percent were passionate haters of the other side.

“In contrast, in 2012, only 26 percent of voters gave the opposing party a neutral or positive rating,” according to the pair. Fifty-six percent had become passionate haters.

Abramowitz and Webster lay the blame for this shift on the growing racial divide between the two parties and an ideological shake-out that has eliminated conservative Democrats and moderate Republicans from the field.

Both parties find it difficult to deal with the “otherness” of the other, the Emory researchers theorize.

The rise of “negative partisanship” means it is no longer enough simply to say the other guy’s wrong. Now he’s wrong – and dangerous. Or a Kenyan. Or something other than Christian.

Or in the case of George W. Bush, he’s a bumbling doofus. “The divide was just as great with Bush,” Abramowitz said.

Respect for loyal opposition has become so rare that it is front-page news when it happens. Literally. The following paragraph was at the top of Wednesday’s Journal-Constitution piece on the Democratic search for a challenger to U.S. Sen. Johnny Isakson:

“Even Democrats like me like Isakson,” said former Gov. Roy Barnes, a Democrat who launched a comeback bid in 2010. “If all Republicans were like Johnny, I would be a Republican.”

Abramowitz said he and his partner began their research as a way to explain why congressional races – for the House as well as the Senate — have become so nationalized, especially in the South.

“It’s not about who you want to be sent to Washington from your district. It’s about what party do you want to be in charge in Washington,” he said. Ideology has become more important than the candidate.

Given the state of Congress, that’s hardly surprising. But what Abramowitz and Webster found was that this no-quarter approach to politics hasn’t stopped in Washington. It has drifted down to the state and local level as well. “Voters are going right down the ballot,” Abramowitz said.

For instance, there are local elections in Dublin that now may be determined by what one thinks of President Obama and his religion. And that’s not good for anyone – on either side of the divide.