Fred Klonsky writes that teachers at 15 charter schools voted overwhelmingly to strike.

Teachers at 15 Chicago charter schools have voted 98 percent to authorize a strike as they continue to bargain a contract with Acero Schools, the largest unionized charter network in the city, and with other charter school networks.

UNO, which later became Acero, founded the charter-school chain in 1998, and it grew quickly with the help of Democratic Party politicians like Governor Pat Quinn and Speaker Michael Madigan. The Governor and the Speaker worked out a 2009 law handing over $98 million in state grant money for UNO to build schools.

For years, the organization and its charter network were run by Juan Rangel, UNO’s clout-heavy chief executive officer.

Rangel was Rahm Emanuel’s mayoral campaign chairman.

Rangel was forced to resign his charter leadership position – with its $275,000-a-year salary – following one of many Rahm school scandals.

In addition to tens of millions of dollars in state funding, UNO received millions more from CPS.

Some politicians, like then-Governor Pat Quinn, distanced themselves from Rangel and UNO after it was reported UNO had paid millions out of the state funding to construction companies owned by brothers of Rangel’s top deputy, Miguel d’Escoto.

In a June 2014 civil settlement the U.S. Securities and Exchange Commission accused UNO of defrauding bond investors by “making materially misleading statements” about the construction contracts.

Rangel later paid a little $10,000 fine.

While operating the schools, which serve largely Hispanic students, UNO was a big spender.

But not on its teachers or classrooms or students.

It charged more than $60,000 for restaurants on Rangel’s American Express “business platinum” card in one year and spent more than $60,000 a year on travel in 2010 and 2011. Records show Rangel flew out of town 31 times in four years at the group’s expense.

Charter teacher salaries are far below those of their counterparts in regular CPS schools. By state law Chicago charter teachers are not covered by the regular CTU contract.