The Chicago Teachers Union on Monday dismissed as “trash” a poll by Stand for Children Illinois showing Lori Lightfoot headed toward a landslide victory over the CTU’s endorsed mayoral candidate, Toni Preckwinkle.

In 2011, the Illinois General Assembly agreed to raise the strike authorization threshold to 75 percent at the behest of Stand for Children, a group that now-former Republican Gov. Bruce Rauner lured to Chicago from Oregon to go toe-to-toe with the CTU.

Chicago teachers were so incensed, they blew past the 75 percent threshold with a vote in which 90 percent backed the strike. While Chicago teachers walked the picket lines for seven days, Rauner kept himself busy excoriating the union in scathing op-eds in the Chicago Tribune.

Last week, that same group — derisively referred to by the CTU as “Stand on Children” — hired California-based FM3 Research to conduct a poll after Lightfoot came seemingly out of nowhere to finish first among 14 candidates vying to replace retiring incumbent Mayor Rahm Emanuel.

The 38-year-old firm’s telephone poll of 400 randomly selected Chicago voters likely to participate in the April 2 runoff was taken Feb. 27 and 28. It has a margin of error of plus or minus 4.9 percentage points.

It showed Lightfoot leading 58 percent to 30 percent, with 12 percent undecided. Lightfoot topped virtually all racial and demographic groups, though her support was weakest among African-Americans, where she led Preckwinkle by 49 percent to 40 percent, just within the margin of error, the survey shows.

Among those polled, Lightfoot also led among women (60 percent); men (56 percent); voters under 50 (54 percent); voters between the ages of 50 and 64 (68 percent); and among voters 65 and older (55 percent).

Lightfoot also led among white voters (62 percent); Latinos (59 percent); college-educated voters (60 percent); voters without a four-year degree (55 percent); liberals (62 percent); moderates (55 percent); and conservatives (54 percent), according to the poll.

CTU Vice President Stacy Davis Gates called the poll “trash” and a last-gasp effort by a dying organization to defeat the union’s endorsed candidate.

“They came into Chicago to break the Chicago Teachers Union and they did not. They have stood in the way of democracy for mothers who have begged for resources in their schools and black women who were begging for their schools to stay open. And they support a privatization movement that is responsible for the decimation of black women working in the Chicago Public Schools,” Davis Gates said Monday.

“The goal is to destroy the Chicago Teachers Union. That has been their goal since they came into town years ago brought in by Bruce Rauner and heralded by Rahm Emanuel. … A Republican think-tank supported by Rahm Emanuel and Bruce Rauner is trying to figure out how it survives in a city that has firmly rejected privatization, the push-out of black people and the anti-Democratic nature of the Chicago Public Schools.”

Mimi Rodman, executive director of Stand for Children Illinois, denied the poll was an attempt to influence a historic election that will bring Chicago its first African-American woman as mayor.

“We went into it with no bias. In fact, we commissioned this poll because we wanted to get the straight-out information,” Rodman said, acknowledging the poll will be one of several factors in determining the group’s upcoming endorsement.

“We are not anti-CTU. We are pro-student. … Our focus is on helping kids. Our focus is a very student-centered approach. … It’s not about an anti-CTU thing at all.”

Rodman also took issue with the charge that Stand for Children Illinois was a pro-Rauner organization.

“We took a great deal of issue with Bruce Rauner and his positions on equitable funding and spent a significant amount of time to fight for this funding formula down in Springfield and absolutely stood up to him,” Rodman said.

In December, the teachers union threw its formidable endorsement behind Preckwinkle a day after the former school teacher embraced the union’s education agenda.

That includes an elected school board, a freeze on new charter schools and public school closings for the four years until that board is seated and “real progressive revenue” to bolster neighborhood schools.

Preckwinkle broke with the CTU on one issue; she opposes a so-called “LaSalle Street tax” now prohibited by state and federal law amid concern it would drive the financial exchanges out of Chicago.

Other mayoral candidates have privately questioned Preckwinkle’s ability to negotiate a new contract with the CTU that beleaguered Chicago taxpayers can afford when she has embraced the union’s education agenda and the CTU has attacked the education plans of other mayoral candidates on her behalf.

Lightfoot also favors an elected school board and a freeze on new charters.