INDIANAPOLIS — Democratic challenger Glenda Ritz pulled off a stunning upset Tuesday night, beating incumbent Republican Tony Bennett in the unexpectedly tight race for Indiana superintendent of public instruction.

Ritz, a public school teacher who switched political parties to take on Bennett, will be the first Democrat to hold the state superintendent’s office since 1971.

“I told you we had a big grass-roots campaign going on,” said Ritz, who waged a low-cost, high-impact campaign with less than one-fifth of the money that Bennett had raised.

Late last week, the independent Howey/DePauw Indiana Battleground Poll showed the race between Bennett and Ritz was tighter than many had anticipated. Just four percentage points separated Ritz from Bennett’s lead, with about 24 percent of voters polled saying they were still undecided.

While Bennett had nearly a 5-to-1 campaign cash advantage, Ritz staged an aggressive, grassroots campaign that made the most out of social media and deployed thousands of teachers to get out an anti-Bennett message.

Those teachers sent out about 100,000 postcards with hand-written messages to family and friends across the state, pleading with them to support Ritz. A group of teachers in heavily Republican Boone County launched a “Republicans for Ritz” site on Facebook, calling on party faithful to split their ticket and vote for the Democrat Ritz.

Typical of the grassroots campaign was the kind of call that Fernando Espinal, 27, got from his fiancee’s mother, a teacher’s assistant at a small-town school in northern Indiana who usually votes Republican.

“She said, ‘Tony Bennett is strangling education. Don’t vote for him,’” said Espinal, who spent Election Day at a union hall in Indianapolis calling Democratic voters to remind them to get to the polls.

Sitting near him was Jacob Miller, 18, who’d just voted for the first time. “Everybody I know said they’re supporting Ritz, whether Democrat or Republican,” Miller said.

Ritz kept up the fight all the way through Election Day when she held a series of press availabilities around central Indiana, while Bennett declined all media interview requests Tuesday.

Brian Howey, editor of Howey Politics Indiana, called the contest the state’s “sleeper race.” Media coverage and interest in the race had been diminished significantly by the higher profile races for a U.S. Senate seat and the governor’s office.

Ritz, a longtime registered Republican who switched party affiliation to run against Bennett, intentionally set up her own campaign headquarters and stayed away from the Democratic field offices.

Yet nationally, the contest has been the radar screen of supporters and opponents alike of the massive education overhaul that Bennett championed with the backing of Republican Gov. Mitch Daniels and the GOP-controlled Legislature.

Those sweeping changes included the rapid expansion of charter schools, creation of the nation’s largest school voucher program, a merit pay system that ties teacher pay and tenure to student performance, more high-stakes testing for grade promotion and graduation, and a controversial to A-to-F evaluation system of the state’s schools.

Bennett’s campaign for his second term focused on those changes as cutting-edge reforms that make Indiana the model for the nation and he promised more to come.

Ritz’s campaign was decidedly anti-Bennett, portraying him as a heavy-handed advocate of top-down decisions that forced federal and state decisions on local schools.

It’s a message that seemed to resonate with some small-government Republicans and with some of the state’s tea party groups who professed unhappiness with some of federal education standards that Bennett seemed to embrace. The Howey/DePauw poll showed that Bennett, who had associated himself strongly with other Republicans on the ticket, was polling at only 68 percent with voters who described themselves as “very conservative” and at 52 percent with voters who called themselves “somewhat conservative.”

And while the poll showed that GOP gubernatorial candidate Mike Pence had 82 percent support from Republican voters, Bennett had only 68 percent support from the Republicans polled. One of the more striking revelations in the poll: Among all female voters polled — Republican, Democrat and independent — Ritz had a 5-point lead over Bennett.

But the poll also showed something that made the race seem even more unpredictable: 24 percent of voters in the Howey/DePauw poll said they were firmly undecided about which candidate to pick.

The campaigns and the messages they delivered couldn’t have been more different. Bennett raised more than $1.5 million in campaign contributions, with some of that money coming from prominent outside sources, including Wal-Mart heiress Alice Walton who donated $200,000 to Bennett’s campaign.

Ritz, meanwhile, raised only about $250,000. In contrast to Bennett’s campaign ads, which started back in September, and were seen around much of the state, Ritz’s campaign didn’t start running TV ads until just days before the election and they were run in a handful of media markets and targeted cable TV stations.

Bennett’s first run for the office was close. In 2008, a late October poll showed Bennett was ahead by 4 points, with about one-third of the voters undecided going into Election Day. Bennett went on to win by a 51-49 percent margin.

Maureen Hayden covers the Statehouse for the CNHI newspapers in Indiana. She can be reached at maureen.hayden@indianamediagroup.com