It seems like a political paradox: Some of the nation’s largest inner-urban school districts – longtime strongholds of teachers unions and their anti-reform orthodoxy – arguably have been among the boldest in experimenting with a wide range of reforms.

Maybe those districts’ hard-pressed school boards – their backs to the wall for so many years in the face of plummeting performance, declining enrollment and a host of other woes – were desperate to try anything. So desperate, they were willing to defy the prevailing, pro-organized labor political culture of such inner-city enclaves. They took up policies like charter schools – and, in some places around the country like Cleveland and Milwaukee, even school vouchers – bitterly resisted by the unions and the rest of the local political establishment.

Hence, the proliferation of autonomous charter schools and other innovations in Denver Public Schools since the early 2000s. A succession of reform-minded school boards (all Democratic, by the way, though technically school-board seats are nonpartisan in Colorado) have pushed forward with policies that have rankled the local union, the Denver Classroom Teachers Association.

The union and its anti-reform allies have pushed back, mounting hard-charging election challenges to the pro-reform board. Denver’s school board elections in fact have turned into a tug-of-war between the two sides, with each pouring cash into the campaigns of their preferred candidates. Well-heeled foundations and other benefactors fund the pro-school choice and pro-reform candidates, and the state and national unions fund the reform foes.

And according to a report this week in Chalkbeat Colorado, Denver is in for another round. Among pro-reform board members targeted as they mount re-election efforts in this November’s election is no less than Democratic former Lt. Gov. Barbara O’Brien. She’s a longtime advocate on children’s issues who fits squarely within her party’s pro-education reform wing. The opponents vying for her at-large board seat include DPS parent Robert Speth, who came close to winning a seat on the board in the last election two years ago.

The upcoming race, as in previous elections, could be a game-changer if critics of the status quo gain the upper hand. Writes Chalbeat’s Melanie Asmar:

O’Brien’s at-large seat is among four on the seven-member board up for grabs this fall. Incumbents are running in three of the four races, and every race is now contested.

The stakes are high: All seven current board members support district leaders’ brand of education reform, which includes closing low-performing schools. Victories by candidates who oppose those reforms would increase disagreement on a board that often votes 7-0. A sweep by those candidates could potentially change the direction of key district policies.

As always, stay tuned.