Hillary Clinton appeared to endorse the Common Core education program during an event Tuesday at an Iowa community college dedicated to education policy.

After one of the students picked to talk to Clinton at the "listening" event gave an impassioned defense the program, Clinton responded by saying that Iowa's version was a good model and it was unfortunate that it was not more widespread.

She did not, however, give an unequivocal endorsement of the national program, which has staunch support and opposition across party lines. Some of its biggest supporters are wealthy Democratic donors who see it as the best way to reform education, while some teachers unions have come out against it because it would link teacher evaluations to student success, which they see as unfair.

In apparent deference to unions, Clinton said teachers should "lead the way" in further developing the program's standards.

The comments came near the end of the event at Kirkwood Community College in Cedar Rapids after one of the five people at the table with Clinton, Diane Temple, a high school teacher and adjunct instructor at the college, said that Iowans were fortunate to have quality education and attributed that to Common Core.

"I worry that not all of America gets to experience this treasure that we have. I think that the Common Core is wonderful step in the right direction of improving American education and it is painful to see that attacked," Temple said. She then asked Clinton, "What can you do to bring that heart back to education in the United States ... and that we offer a quality education to all Americans?"

Clinton called Temple's remarks a "powerful, touching comment that I absolutely embrace." She said it was "very painful" to see the "really unfortunate" argument surrounding Common Core since it began as a "bipartisan effort ... actually, nonpartisan" project.

"It wasn't politicized. It was about coming up with a core of learning that we might expect students to achieve across our country, no matter what kind of school district they were in, no matter how poor their family was. That there wouldn't be two tiers of education," Clinton said.

She added that, "Iowa has had a testing system based on a core curriculum for a really long time. And you see the value of it. You understand why that helps you organize your whole education system. A lot of states, unfortunately, haven't had that. So [they] don't understand the value of a core, in this sense a common core. Of course, [then] you can figure out the best way in your community to try to reach."

The question apparently caught Clinton off-guard. She has rarely spoken on the controversial program, which is largely a project of state governors.

The American Federation of Teachers, a staunch ally of Democrats, had previously supported Common Core, but backed away into a more neutral position after staunch opposition from rank-and-file members. The National Education Association, the other major union and also a Democratic ally, slammed the standards last year, saying they should be rewritten with teacher input.

Common Core supporters within the Democratic Party have called for Clinton to give the standards more forthright support but noted it would be tricky for her.

"She has had more longstanding ties to the teachers' union, certainly, than Obama ever had. She's thrown some bones to both sides and I think is sort of trying to triangulate on this," Whitney Tilson, a board member of Democrats for Education Reform, told the New York Times last month.