State Sen. John Liu is like the proverbial schoolkid who brings his teacher a shiny apple each morning — except he’s a teachers union pet, who gets showered with campaign cash for continued gifts to New York’s most powerful special interest.

It’s not just his relentless war on charter schools: He’s also helped force the city to hire more teacher-union members and more directly undermine Mayor Eric Adams’ control of the Department of Education.

Liu, chairman of the New York City Education Committee, has raked in $33,300 in teachers’ union cash since his first Senate race in 2018. He ranks third behind his Senate colleagues John Mannion (D-Syracuse) and Monica Martinez (D-Happauge), both former teachers and thus actual union members.

The cash came from both the New York State United Teachers — parent of the city’s powerful United Federation of Teachers — and its Voice of Teachers for Education PAC.

And those donations surely were important to Liu winning the Democratic primary in 2018, when he narrowly defeated incumbent Tony Avella after losing to him in 2014 as the teachers unions joined a broader left-leaning alliance to purge moderate Dems.

To be clear, Liu’s always been a stalwart backer of the teachers’ unions, through prior runs for City Council, city Comptroller and mayor; the UFT donated $12,375 into his campaign coffers over that period. He once said the city should “get rid of” large charter school networks — the ones that lead the way in fighting to keep these alternative schools alive despite the unions’ enmity.

The unions play the long game, relentlessly and ruthlessly, supporting the rise of friends like Liu, Mannion and Martinez — as well as pals in Republican ranks, such as state Sens. James Tedisco (Saratoga) and Daniel Stec (Glen Falls). Without such allies, the Legislature might heed the public, which clearly supports more charters and doesn’t want the mayor’s power over the DOE compromised.

The risk for Liu is that his Queens constituents are getting tired of how the UFT agenda increasingly ignores their wants and needs, as the union and its far-left allies work to de-emphasize excellence in the public schools and demonize Asian-American students’ hard-earned success — even as they also try to close off any school-choice escape hatch.

We look forward to this apple-polisher’s comeuppance.