A new law Gov. Pat Quinn is expected to sign tomorrow will let Chicago have 75 charter schools, up from the current cap of 30. That’s 45 more for the city and, overall, twice as many charters statewide.

That’s fantastic news for charter school backers (notably, a coalition comprising charter schools), who themselves wanted to see the cap lifted completely.

“Thursday’s event will mark a watershed moment for the future of thousands of Illinois families and a nation’s call to action,” the Illinois Network of Charter Schools said in a news release about the bill-signing.

It also puts Illinois ahead of other states in President Obama’s “race to the top” challenge, says Matt Vanover, the spokesman for the Illinois State Board of Education.

“The Obama administration has made it clear that they would like to see more charter schools,” Vanover says.

Raising the cap means CPS could start moving more aggressively on its Renaissance 2010 goals of opening more charter schools.

The bill Quinn is set to sign has other provisions, as well. Charters will have to file annual audits with ISBE, and every two years, ISBE will have to give the governor and a legislature a report on charter schools statewide.

The Chicago Teachers Union spent the better part of a year negotiating the bill, officials say.

“We do agree with some of the things in there, we don’t agree with everything, and so we agreed to be neutral, we agreed not to oppose the bill,” says Traci Cobb-Evans, who handles legislative issues for CTU.

In particular, the changes that will boost accountability by requiring more audits and reports are welcome, Cobb-Evans says. The union stresses that the underlying issue isn’t that charter schools are usually non-union.

Rather, it’s that “we want the same quality public education and certification guidelines in all Chicago public schools,” spokeswoman Rosemaria Genova says, not a “two-tier system.”

The union, incidentally, supports a companion bill that would make it easier for charter school teachers to unionize. Aren’t you glad you read my last link roundup, which pointed out that very trend just the other day?