A Kentucky high school math teacher with no political experience unseated one of the state’s most powerful Republican lawmakers in Tuesday’s primary elections — a sign that the widespread teacher unrest could turn into a potent political force in November.

Travis Brenda, a teacher in Rockcastle County, narrowly defeated House Majority Floor Leader Jonathan Shell, a rising GOP star endorsed by Senate Majority Leader Mitch McConnell, according to the Lexington Herald-Leader.

It was Brenda’s first bid for public office, and he was channeling teachers’ anger at state lawmakers who voted to roll back pension benefits for teachers and state employees. Shell co-authored the controversial bill, which moved all incoming teachers into a hybrid pension system that operates more like a 401(k). Lawmakers voted for the bill in a hurry on one of the last days of the legislative session, and the bill’s text was never made available to the public before the vote.

Republican Gov. Matt Bevin signed the bill, prompting thousands of teachers to rally at the state capitol in April, closing schools in more than 30 districts.

Anger about the pension bill and the resulting backlash from educators pushed dozens of teachers in the state to run for office. At least 40 educators and former teachers have put their names on the ballot, according to the Associated Press. About 16 of those candidates had primaries on Tuesday, and seven of them won.

Shell and three other Republican incumbents faced primary challenges from a teacher on Tuesday, but he was the only one to lose — though he was also the only one who voted for the pension bill. Republicans currently hold the state’s House of Representatives, which they wrestled away from Democrats in 2016 — the first time Republicans have taken control of the state House, Senate, and governorship. The GOP holds 63 seats in the House compared to 37 seats held by Democrats.

Brenda, who unseated Shell, describes himself “as a life-long conservative, an advocate of the 2nd Amendment, pro-life and believes in common sense solutions.” But he was critical of Kentucky lawmakers who raised taxes on the middle class to fund education.

The teachers strikes in Kentucky were not enough to stop lawmakers from rolling back their pension benefits, but teachers did succeed in pressuring lawmakers to boost education funding — though they did that by raising taxes on everyone except the wealthiest Kentuckians.

In November, Brenda will join at least 30 other teachers and former teachers who are on ballots in various state races. The outcome of those races may indicate the long-term political strength of the teachers’ labor movement.